May 1S9Q.] 



PSYCHE. 



345 



height of the cylinder, with a central 

 trigonate nick to guide the lancet, and 

 finally again the tube is almost com- 

 pleted just before the tip. This tip has 

 exactly the shape of the opening at the 

 tip of the opercular sheath and fills it 

 completely. It is perhaps questionable 

 whether this organ is used in piercing 

 or is even inserted into the wound. The 

 hypopharynx or lancet is a simple half 

 tube. In Stomoxys calcitrans the 

 structure of the canula is diflerent and 

 much more simple, being uniform until 

 just below the extreme tip and there the 

 tube is completed. 



The opercular sheath contains con- 

 siderable muscular and other structure 

 which was not studied. From the base 

 of the hypopharynx a ringed tube leads 

 direct into the fulcrum which is the 

 sucking or pumping organ. From the 

 base of the canula on each side the 

 ''great tendons" of Macloskie extend 

 along the side of the fulcrum nearly to 

 the top. These are according to Dim- 

 mock "the remnants of the basal chiti- 

 nous supports of the maxilla." They 

 are securely attached to the canula and 

 I could not find any point of attachment 

 at the other extremities. In separating 

 the parts of the mouth they always 

 remain attached to the canula. In spe- 

 cimens mounted in balsam no muscular 

 structure is observable attached to them. 

 The fulcrum is funnel shaped as shown 

 in the figure, and to the upper margin 

 the very long heavy palpi are attached. 

 In Stomoxys calcitrans the fulcrum is 

 quite diflerent in shape, quadrate conic 

 rather than cylindric, the very small 



palpi attached to the frontal lateral sup- 

 porting rods rather close to the lower 

 part of the fulcrum and therefore essen^ 

 tially different in location and more like 

 Mil sea. 



The palpi in Haematobla are quite 

 densely set with stout spinous hair. 



Dr. Macloskie is studying Stomoxys 

 and Haematobla., and he will undoubt- 

 edly be able to complete and elaborate 

 this rough outline structure. 



In examining the wings I noticetl a 



yiy 



d 



Fig. 3. 

 curious difference between the main 

 wing and the alar appendix. The for- 

 mer is of the common membranous 

 structure clothed with very fine pubes- 

 cence, the margins ciliated and not 

 thickened. The appendix shows no 

 pubescence but is minutely and rather 

 densely punctulate. The margin is 

 formed by a spiral, coil-like tracheate 

 structure. The veins also show differ- 

 ences in structure. The main trunks 

 are complete, continuous tubes set with 

 fine, rather short hair. The auxilliary 

 veins which do not reach the base, and 

 some of the transverse veins, are distinct- 

 ly ringed and segmented, the segments 

 set with transverse rows of minute hair. 

 Whether this indicates the original tra- 

 cheate nature of these veins I cannot 

 say. 



