LOUISIANA CIRCULAR No. 6. 



23 



b< ar sj )i nicies. When it becomes full grown the larva makes its 

 own cocoon of earth a, id silk, united in such a way that the re- 



l''i;. lo. (Jray horsefly (Tabanus cymatophorus), 

 female, enlarged to one and a half diameters. 



aiilt is a rather dense structure which appears as if moulded 

 from a. poor grade of cement. The cocoon finished, the larva re- 

 mains in it unchanged for some length of time, just how long 

 I have not been able to determine for several reasons. 



The cocoon varies in size to an extent that is quite notice- 

 able, and one is led to suspect that the smaller cocoons contain 

 the males and the larger ones the females. It was proven by 

 several observations that the nests which contained the small 

 cocoons had not received as large supplies of food as those con- 

 taining the large cocoons, and the smaller ones were noticeably 

 lighter in coloration. 



The adult is a conspicuous wasp more than an inch in 

 length, with a well-developed sting which she can use effectively 

 b case she gets in a tight place, but she 'never attempts to pro- 

 tect, her nesting site or her young by stinging the intruder, as 

 s'rne wasps do. Both sexes are black in general coloration, with 

 the legs largely yellow, and small spots on the sides of the thorax 

 ;md larger spots on the abdomen greenish yellow. Several fe- 

 nides may have nests in close proximity to one another, but each 

 attends to its own, and on this account the species is often re- 

 ferred to as a solitary wasp, as distinguished from the the hornets 

 ni id oilier wasps which form a group known as sue in 1 wasps. The 

 n(,st is a simple burrow excavated in the soft sand by the fe- 

 male herself, at least in cases observed, and in this burrow the 



