98 
peculiar and interesting. ‘They are quite sharp, strong, slightly curved, 
and carried in a groove along the dorsal lateral side of the head when not 
in use. When in action they are rapidly thrust outwards and downwards 
(Fig. 26), the two generally working in unison and literally tearing the 
skin of the prey. Sometimes this operation is repeated several times 
and at different points on the body of the grub before any attempt at 
feeding is made. The writer has had his hand so severely punctured by 
the mandibles that itching or stinging lasted for several hours. In our 
eS aut cece 
Fig. 27. Tabanus suleifrons Macq., larva. 
tin boxes the host grub sometimes prepared a cell, and the tabanid larva 
often made an entrance to the cell just large enough for its head and 
the fore part of its body, thus enabling it to withdraw, if necessary, to 
a safe distance from the grub. This strategy is also frequently adopted 
by asilid larvae. The Tabanus larvae can crawl about and penetrate 
the earth quite freely. They prefer moist places. They no doubt feed 
on various soft-bodied underground insects, and probably on earthworms 
also. This species and T. atratus can pass long periods without food— 
a capacity frequent among predaceous larvae living under similar con- 
ditions. 
The adult is one of the common horse-flies and is often so. abundant 
as to be a serious stock pest. It is distributed from New Jersey to Lou- 
isiana and Missouri. It is of large size, varying in length from 17 to 20 
mm.; the large compound eyes are typical of the family; the under 
surface of the thorax is densely covered with a grayish pubescence, the 
upper surface with alternate black and grayish brown longitudinal mark- 
Fic. 28. Tabanus atratus Fabr., larva. 
ings; the dorsum of the abdomen is reddish brown, with yellowish white 
triangles on segments two to five; the wings are transparent, with certain 
areas of the veins margined with brown (Pl. IX, Fig. 34, 35). The 
eggs have not been described, but they are probably dull-colored and 
laid in masses like those of related species. The larva (Fig. 27) of this 
species, which measures about 30 mm. in length when full-grown, is 
glossy, semitransparent white with delicate, almost microscopic, longi- 
