emery: SIMULIUM VITTATUM in KANSAS. 343 



has made experiments to ti'ansmlt pellagra to a monkey, by 

 first letting the flies bite a pellagrin and then bite a monkey. 

 The full significance of the relation of Simulmm to the trans- 

 mission of pellagra has not yet been determined. 



MOUTH PARTS OF SIMULIUM VITTATUM. 



The question of determining the mouth parts of S. vittatiim 

 I have attempted to answer, both by their location or place of 

 attachment and by their function as given for the mouth parts 

 of insects in general, and especially those of Diptera, by Dim- 

 mock, Krsepelin, Packard, Meinert, and J. H. Smith. 



Mandibles. 



Packard says : "Mandibles are wanting in the imago male 

 Diptera and the females of all flies except Culicidse and 

 Tabanida?."" 



In "The Skeleton of the Head of Insects," by Comstock and 

 Chujiro Kochi, it says, "To this part," the clypeus, "one con- 

 dyle (the ventral) of the mandible articulates." Now there is 

 such an attachment as this in Sirmdaim mouth parts, as is 

 shown in plate XXXIX, figure 21, plate XLI, figure 28, female, 

 and plate XLI, figure 29, for the male. This forms an excep- 

 tion to Packard's statement quoted above. In Simulmm the 

 mandible has a basal piece similar to the stipes of the maxilla. 

 (PI. XL, fig. 22c.) The .serrate edge of the mandible has 

 about thirty-two saw-like teeth on its end and sides. 



Labrum and Hypopharynx. 



The next part in question is the presence of a labrum. 

 Krsepelin says: "The labrum (oberlippe) appears as the 

 direct continuation forward of the upper anterior margin of 

 the basi-proboscis. It has a groove on its under surface, and 

 is in fact an inverted semicylinder with double walls."" Pack- 

 ard quotes Meinert as follows : "The hypopharynx, most gen- 

 erally free, more or less produced, acute anteriorly, forms 

 with the labrum the tube of the pump (antlife)."'^ 



A careful dissection of S. vittatura mouth parts shows that 

 the part Smith called rods of the mandibles (pi. XXXIX, 

 fig. 23, L, and pi. XLI, fig. 28) is the labrum, and that it is 

 connected at its base with the hypopharynx. Plate XXXIX, 



6. Packard, k. S., A Text Book of Entomology, p. 62. 



7. Krsepelin's Proboscis of Musca. 



S. Packard, A. S., A Text Book of Entomology, p. 78, 



