The Mouth-parts of the Nemocera, etc By W. Wesche. 35 



at the extremity, and the paraglossa? of the labium resemble those 

 found in the Chironomyda? (pi. IV. fig 17). 



The paraglossa?, in some species of Psychoda, are hardened, and 

 furnished with three minute teeth on the extremities ; these are 

 not to be confounded with the teeth in the Muscida?, having no 

 homology, being modified hairs. P. phalccnoidcs L. and P. sex- 

 punctata Curt, are of this type. In Ulomyia and others the para- 

 glossa? are as in Chironomus, Bibio, Sciara, and may be considered 

 as characteristic of the jSTemocera. The maxilla? are brush-like in 

 appearance, carry four-jointed palpi, which are joined on to the 

 stipites as in Culex. The hypopharynx is ciliated all down the 

 sides (pi. V. fig. 1). 



In this family, when the mouth is used for blood-sucking, the 

 offensive weapon seems to be the labium, and the other ciliated 

 organs seem adapted to carrying up the fluids by capillary attrac- 

 tion. In Britain these insects are not known to bite, and indeed 

 it is very doubtful if they feed at all, as in a number of specimens 

 examined, no food has been found in the abdomen, and it seems 

 difficult to recognise any alimentary canal. 



The males in Culex are peculiar, as their mouth-parts differ 

 from those of the females ; the mandibles are mostly aborted, and 

 the maxilla? appear to be in an atrophying condition. Occasionally 

 a male is found with developed mouth-parts, but these are decidedly 

 less perfect than the weapons of the female ; I have lately examined 

 a number of males of the species enumerated on a previous page, 

 besides many C. pipiens. I only found one Anopheles maculipennis 

 with complete mouth-parts, and of these the mandibles and maxilhe 

 are in an atrophied state. I have also a record of a male C. pipiens 

 in September 1902 with complete tropin (pi. V. figs. 2-5). In 

 the males of all the species, is a surprising reversion ; the hypo- 

 pharynx, unlike that of the female, is ciliated at the tip ; the palpi 

 also are four-jointed, and hinge on to the maxillary stipites and 

 cardines. In Dinoccritcs cancer the larva? are parasitic on the crabs 

 in the Barbadoes ; the palpi in the males are very short, but the 

 remains of the four joints can still be made out. In some species 

 the males are thought to sting; in Siegomyia fasciata, the host of 

 the yellow-fever germ, he is reported to act in this manner. I have 

 dissected the tropin of several males, and I found very short 

 atrophying maxilla?, no mandibles, a ciliated hypopharynx, and 

 the labrurn and labium well developed. In August, 1903, I had a 

 number of males of C. pipiens, C. annulatus, and A. maculipennis, 

 and, with the exception mentioned, the trophi were in the same 

 state as in Stegomyia. Not one of these males had his abdomen 

 distended with food, though many had been in my sleeping chamber 

 all night ; and I have little hesitation in saying that normally 

 the males do not suck blood, and I even doubt that they feed at all. 

 Occasionally an aberrant male appears with fully developed mont'.i- 



D 2 



