258 THE MONTHLY BULLETIN. 



This is to prevent egg-laying by the female. A weak solution of carbolic 

 acid emulsion sprayed repeatedly over the plants will keep the flies 

 away. Fertilizers such as kainit, nitrate of soda and superphosphate 

 applied at the rate of from 1,000 to 1,500 pounds of kainit, 100 pounds 

 of nitrate of soda, and 200 pounds of superphosphate per acre are 

 recommended. Gas lime applied around each plant has afforded some 

 protection.* 



Carbon bisulfid, though an expensive remedy, is effectual. A special 

 tarred card placed around the base of cabbage and cauliflower plants 

 prevents the flies depositing their eggs upon the stem. 



Plowing and thorough cultivation are recommended as giving excel- 

 lent results in the control of this pest. A badly infested field should be 

 thoroughly plowed and cultivated as early as possible to destroy the 

 pupffi. 



Natural Enemies. — A small parasitic insect has been reared from the 

 puparia. Twelve were obtained from a single one. This has not been 

 determined and is probably responsible for the maggots not doing more 

 serious damage in this State. 



TACHINID^ (Family). 



THE TACHINA FLIES. 



This is one of the most beneficial families of insects, because of the 

 parasitic habits of the larvae upon destructive caterpillars, grasshoppers, 

 bugs, beetles, sawflies, etc. 



The adults are little larger than house flies, being striped and gray- 

 ish in color with hairy bodies. They are only active on Avarm days. 

 The eggs are usually white and stuck to the living larvae (Fig. 142) 

 upon which the coming maggot is to feed. Upon hatching the larvae 

 bore through the skin of the host, nourishing themselves throughout 

 their development upon the internal tissues, avoiding the destruction 

 of the vital organs until ready to pupate. When the host is destroyed 

 they leave the old carcass and form hard brown puparia near the sur- 

 face of the ground. The adults issue from these in a very short time. 

 Breeding is rapid, there being several generations each year. 



THE DIABROTICA PARASITE. 



Celatoria diahroticcc Shim. 



(Celatoria crawii Coq.) 



(Fig. 256.) 



General Appearance. — Grayish black flies with white face, black 

 antenme and legs, grayish black thorax and abdomen. The adult males 

 have a peculiar large flattened process on the underside of the second 

 abdominal segment. The length is about one eighth of an inch. The 

 larvffi are white and the puparia dark brown. 



♦Circular No. 63, Bur. Ent. U. S. Dept. Agrcl. p. 3. 



