Morphology of the antennal sensilla of Rhus gall aphids (Hemiptera: Aphidoidea: Pemphiginae): A comparative analysis of five genera

Rhus gall aphids induce sealed galls which are rich in tannic acid and have been widely used for chemical and medicinal purposes. Identification of these aphids at the genus and species levels can be a challenge due to their morphological similarity and unusually complex life cycles. The external morphology of the antennae of 11 taxa was examined by both light and scanning electron microscopy, each antenna comprising a basal scape, a pedicel, and an elongate flagellum of three or four segments covered with secondary sensilla of five morphologically distinct types. Aphids with Rhus chinensis as primary host have five antennal segments; those with R. potaninii and R. punjabensis var. sinica as hosts have six segments. In Schlechtendalia species, each flagellar segment is covered with a large placoid sensillum that is separated by sunken grooves and appears as irregular plates with numerous microtrichia. In Nurudea species, the secondary sensilla look like annular rings, with the surface almost fully covered with microtrichia. Floraphis meitanensis has annular sensilla with smooth surfaces, and each ring is surrounded by longer microtrichia. Meitanaphis and Kaburagia species have a large sheet secondary sensillum occupying half to three-fourths of the area of each flagellar segment. The secondary sensilla of two species of Meitanaphis showed great differences indicating the need for revision of the genus.

The distal sperm flagellum: its potential for motility after separation from the basal structures.

The distal region of the sperm flagellum of Gallus domesticus has been separated and purified. It consists of a 9+2 axoneme, without basal or accessory structures. Such distal segments have been demembranated and then reactivated, either by adding ATP or by releasing ATP photolytically from caged ATP: we find that they are capable of a period of independent motility. Bends form repetitively and travel towards the tip, though it is an abnormal, irregular pattern of beating. It is argued that this motility is not dependent on damage to the flagellum at the fracture site. Evidence is presented that the potential for such motility depends upon the existence of bends on the axoneme before the reactivation. The reactivated motility is short-lived: 50 % of the distal flagellar segments, placed in the reactivating solution, become quiescent and straight within 60 s. However, vigorous beating can be induced in such quiescent segments of axoneme by compressing one end with a glass microneedle. We record, provisionally, that the site of compression does not determine the direction in which bends move along the flagellar segment. The effect of compression in re-initiating motility suggests that a mechanical resistance is necessary, somewhere along the axoneme, for normal, sustained motility; it is proposed that the specialized basal structures, collectively, provide such a resistance in the intact flagellum.

NOTES ON GENERAL MORPHOLOGY AND TERMINOLOGY OF THE CHIRONOMIDAE (DIPTERA)

Some morphological terms and characters of Chironomidae are discussed. The proposed terminology of the head chaetotaxy is more in accordance with that of other Diptera. The term flagellomere is preferred instead of flagellar segment. The morphology and terminology of tentorium, cibarial pump, maxillary palp, ocelli, and thorax including humeral pit are given special attention. Suggested terminology for the male hypopygium is as follows: gonocoxite and gonostylus for the major genital claspers, volsellae (consisting of claspette and endomere) for the appendices, phallapodeme, sternapodeme, and coxapodeme for the endoskeleton and aedeagal lobe for the "Dritte Spange". The term seta is preferred to such terms as hair, bristle, etc. It is suggested that in the larvae the name premandible be retained for the moment. There seems to be strong evidence for applying the term mentum instead of "hypostomial plate", "hypochilum", or "labial plate". The mentum seems to consist of two plates for which the terms ventromentum and dorsomentum are proposed. The "paralabial plates" are parts of the ventromentum and can be termed ventromental plates. A more correct name for the "glossa" seems to be ligula.

A NEW SCHIZOPYGA FROM CANADA (HYMENOP.; ICHNEUMONIDAE)

Female.—Length 7 mm. Head thick antero-posteriorly, the temples scarcely narrowed behind, distinctly broader than eyes viewed dorsally; vertex evenly convex; ocelli small ; ocellocular space fully three times diameter of lateral ocellus; malar space scarcely half basal width of mandible; face distinctly elevated above level of eye-margins, feebly shining with well separated fine punctures, the interspaces finely reticulately sculptured; antennae 23 segmented, first flagellar segment very nearly equal to second and third combined; thorax shining; propleura polished almost without punctures ; mesoscutum with only sparse punctures bearing vestiture ; mesopleura sparsely punctate above and polished impunctate behind, anteriorly and ventrally the punctures becoming more dense toward a patch of very fine dense punctures adjacent epicneimia; metapleura with larger shallow punctures which are somewhat confused by weak rugulae below; propodeum rather elongate, shining, impunctate, dorsally finely and faintly reticulate, median parallel longitudinal carinae very weak, lateral longitudinal carina distinct only on posterior half, apical transverse carina defined laterally but scarcely visible at middle; lateral face of propodeuin a little roughened; nervulus slightly postfurcal, nervellus broken about at middle.

Lestodiplosis alvei sp.n. (Diptera, Cecidomyidae)

Male. Length about 1·5 mm. Antennae slightly longer than head, thorax and abdomen: 2 + 12, basal enlargement of flagellar segments with regular ring of moderately long stout setae and one ring of circumfila, distal enlargement with two rings of circumfila and irregular ring of stout setae, loops of circumfila regular and moderately long, those on basal enlargement extending about one-third length of stem, distal ring on distal enlargement extending about two-thirds length of neck; 1st and 2nd flagellar segments fused; 3rd flagellar segment with stem about three times as long as broad, neck slightly longer, about three-and-a-half times as long as broad, distal end slightly darkened as on all flagellar segments; 10th flagellar segment with stem about four times as long as broad, neck slightly longer in proportion. Palpi quadriarticulate with few setae: proximal segment quadrate, 2nd just over three times as long as broad, 3rd about three times as long as broad, the same width as 2nd, distal segment about four times as long as broad, slightly narrower than two previous segments. Thorax brown. Wings hyaline; 3rd vein reaching margin at apex of wing. Legs hairy; claws moderately curved, simple; empodium slightly shorter than claws. Genitalia: basal clasp segment long narrow, small basal lobe prominent; distal clasp segment long narrow, darkened; dorsal lamella moderate length and breadth, distinctly longer than ventral lamella, deeply emarginate, each lobe rounded; ventral lamella comparatively short but broad; style long, moderately stout.

A NEW SPECIES OF MACROCENTRUS FROM NOVA SCOTIA (HYMENOP.)

Female.—Length 7 mm. Head very little wider than thorax, cheeks, viewed from the side, broader than the temples; face much broader than long, shallowly sparsely punctate; eyes large, prominent; malar space about as long as basal width of mandible; clypeus convex, much less than twice as broad as long, the anterior margin truncate; distance from clypeal foveae to eyes about equal to length of clypeus; lateral ocelli not distinctly larger than median ocellus; longest segment of maxillary palpus distinctly shorter than second segment of antennal flagellum; apical segment of labial palpus much longer than preceding segment; antennae of the type broken, seven segments of flagellum present; first flagellar segment about as long as height of eyes.