MOSQUITOES 407 



5. Pulex fasciatus, Bosc. 



This flea is also found on the rat and will attack man. It 

 has eighteen teeth on the prothoracic comb and no black spines 

 on the head. 



6. Pulex pallipes is another species found on the rat and man. 

 7. Typhlopsylla musculi, Duges (The Rat Flea). 



In the genus Typhlopsylla the body is narrow and elongated, 

 and on the under side of the head are numerous chitinous bristles, 

 and also on the pronotum. This rat flea is also found on the 

 vole ; it is dark yellowish-brown and the body attenuated in front, 

 and there is a distinct comb on the posterior margin of the pro- 

 notum ; the legs have very few hairs, femora bare and curved ; 

 tibiae with black bristles ; four spines on the genae. 



An allied species, T. assimilis, Taschenberg, occurs on mice, 

 shrews, moles, and voles ; it has only three genal spines. F. V. T.] 



SYSTEMATIC, ANATOMICAL, AND BIOLOGICAL REMARKS ON 



MOSQUITOES. 



Mosquitoes Nematocera form one of the four sub-orders of the Diptera, 

 and are divided into numerous families, of which, however, only the 

 CulicidcB are of interest to us here. The head is small, the facetted eyes 

 are placed laterally, but there are no accessory eyes (ocelli). In front 

 of the eyes are situated the comparatively long antennae, the differences 

 of which strongly mark the distinction of sex. 1 



The antennae are composed of fifteen or sixteen segments. In the male 

 they are covered with long whorl-like hairs, while in the female the 

 antennal hairs are short differences that are perceptible even with the 

 naked eye. 2 The proboscis, which is longer than the antennae, protrudes from 

 the inferior aspect of the head and is composed of the following parts (figs. 264 

 and 265) : Two grooved half tubes, facing one another, of which the upper one 

 is the upper lip (labium), and the lower one the lower lip (labrum), which 

 represents a pair of coalesced maxillae. Within the tube formed by the 

 labrum and labium are the mandibles and maxillae, transformed into instru- 

 ments for piercing, and a single puncturing organ, the hypopharynx. On 

 the right and left, next to the proboscis, are placed the straight five- 



1 [This is by no means always the case ; in the genera Deinocerites, Wyeomyia, 

 Limatus, Theobald, and in Sabethes, Robineau Desvoidy, they are nearly the same 

 in both sexes. F. V. T.] 



- [This is not always the case, vide previous note. F. V. T.I 



