hungerford: anatomy of simulium vittatum. 381 



The oviduct connecting the ovarian sac with the exterior is 

 comparatively easy to trace in the early adult stage. Here the 

 oviducts are seen to join, forming a short tube, "the vagina," 

 which passes to the genicular opening on the ventral side of 

 the body between the penultimate and antipenultimate seg- 

 ments. (Fig. 8.) Dorsocaudad of the vagina lies a small 

 chitinized spherical pouch, the spermathecse. (Fig. 7.) This 

 spermatheca is .09 mm. in diameter and dark-brown in color, 

 with a thick chitinous covering. It is attached to the distal end 

 of the common oviduct by a white cylindrical tube. The attach- 

 ment of this white tube to this hard brown sphere reminds 

 one of a germinating seed. It is interesting to note that with 

 this fly there is but one functional spermatheca. In all the 

 related species of flies that have been studied there are two — 

 Phlebotomus, Musca domestica, S. calciti-ans, Culex and the 

 chironomids have two. When the genital apparatus is dis- 

 sected and stained with borax carmine the two accessory 

 pouches shown in figure 7 are found to be glandular in nature. 



In concluding this brief sketch of the anatomy of the sand 

 fly it may be well to state : 



1st. That the three blood-sucking species studied for com- 

 parison of internal structures conform quite closely to the one 

 here reported. 



2d. That the digestive tract has three enlargements: the 

 fore part of the proventriculus, the stomach, and the rectal 

 pouch which contains six glandular rectal papillse. 



3d. That it is joined in the pharynx by the common duct of 

 a pair of salivary glands which are located cephalo-dorsad to 

 the proventriculus and well forward in the shoulder of the 

 thorax, and at the junction of mid and hind gut, by four Mal- 

 pighian tubules. 



4th. That the reproductive organs are similar to those of 

 related insects, save that but one spermatheca is found and 

 this lies to the left side. 



