108 GNATS OK MOSQUITOES— CHAPTEll VI 



spines, within which may be distinguished an elongated 

 embryo, and a pecuhar sac at one pole containing a single 

 large polynucleated cell, which appears to be in some way 

 concerned in the bursting of the egg membranes ; the whole 

 being enclosed in a delicate, structureless, external mem- 

 brane, the total length of the whole egg being 0'71 mm. 

 Their width is but a fifth of their length, and they are much 

 broader at the end provided with the polar capsule, the base 

 of which is marked with fine radiating stria;. In the 

 oviduct this broad end always hes forward, so that the 

 narrow pointed end is that which appears first in dehvery. 

 The ovaries communicate with the common oviduct by 

 means of a short, transparent, funnel-shaped tube ; and this 

 latter is a short transparent canal, which commencing in 

 the junction of the funnels of the ovarian ducts, runs straight 

 backwards without convolution or deviation from the middle 

 line, to open between, and at the base of, the ovipositors. 

 Just before its external termination, it receives on either 

 side the ducts of three small glandular bodies, each con- 

 sisting of a spherical glandular portion about 05 mm. in 

 diameter and a short neck or duct. They are filled with an 

 opaline white fluid, which consists of a material identical 

 with that found in the receptaculce seminales of the male, 

 the peculiar fibrous matrix as well as the spermatic elements 

 being undoubtedly transferred en manse from the receptacles 

 of the male to those of the female, their contents differing 

 only in the fact that, whereas in the male only the earlier 

 stages of spermatogenesis are represented, in the female, the 

 contents consist of more advanced spermatic elements and 

 of fully developed spermatozoa, so that the later stages of 

 the process take place in the body, not of the male, but of 

 the female. 



The spermatozoa are minute comma-shaped bodies with 

 a rather stiff one-sided tail, and a pear-shaped nucleus, the 

 long diameter of the head being about 7 iii. I see no reason 

 for thinking that these bodies serve any other function than 

 that of spermotheca:", and their dull colour is due, not to 

 any opacity of their contents, but to the sooty pigmentation 

 of the sac-wall. They contain absolutely no glandular 



