1913] Stomoxys calcitrans Linn. 199 



The uterine glands, (u. g.), are two rather stout tubular 

 organs with slightly bulbous extremities. The bulbous end 

 is firmly joined to the lateral oviduct by a very short double 

 strain of connective tissue. 



The receptacula seminis are two small, black, spherical 

 bodies, each with a cellular socket resembling the fitting of an 

 acorn cup. From this runs a very fine duct which enters the 

 division between the oviduct and the uterus in the mid-dorsal 

 line. The receptacula are attached to each other but can be 

 separated by dissection. The uterus is a tube of the same 

 diameter as the common oviduct above, and runs down the 

 middle line into the ovipositor. 



The ovipositor consists of three cylindrical segments of 

 thin chitin which usually lie telescoped inside the abdomen. 



Habitat. 

 Farmyards and stables are evidently the favorite haunts of 

 this fly. It occurs also in fields and open woods, especially 

 where cattle or horses are grazing. It is evidently by no 

 means uncommon even in large cities, and numbers have 

 been seen in quite busy streets. It is fond of resting on sur- 

 faces fully exposed to the sun, such as doors, gates, and rails, 

 and to a less extent also on stone walls. Painted surfaces 

 seem to be specially attractive to it. Its flight is quite in- 

 audible at a short distance. When disturbed it frequently 

 returns to the same spot, as though it were a favorite resting 

 place. It is quite active during the warmer part of the day, 

 and at night returns to some sheltered spot such as the beams 

 in a shed. In Columbus the numbers of this species dwindled 

 towards the end of October in 1912, but a few could be caught 

 up to the end of November, and four specimens were taken on 

 December 3rd. In captivity these flies live but a short time, 

 generally less than a week. They frequently clean their wings, 

 performing their cleaning with great precision, the hind pair 

 of legs being used for this purpose. The lower surface is 

 combed, then the upper, the legs are then rubbed together and 

 the process repeated. 



Emergence from the egg. 



The larva makes its escape from the egg by splitting the 

 broad end of the groove, leaving it slightly raised, and apparently 

 intact on the opposite side, Plate XXII, Figure 1. 



