4 BULLETIN" 221, TJ. S. DEPARTMENT OF AGRICULTURE. 



on other plants at egg-laying time. In the laboratory, under arti- 

 ficial conditions, the eggs will hatch in from 6 to 10 days, rarely go- 

 ing as long as 15 days. Eggs have been observed from early April 

 in northern Texas till the middle of May in Kansas. 



THE LARVA. 



y^g^feg^. 



Fig. 2. — The southern corn leaf-beetle: 

 Eggs. (Original.) 



The newly-hatched larva? are nearly cylindrical, about 1 mm. 

 long and 0.03 mm. in diameter, tapering slightly and becoming 



somewhat flattened toward the posterior 

 extremity. They are pale yellow, except 

 the first thoracic segment and head, 

 which are creamy white. The head is a 

 little broader than the thorax, and the 

 body is covered with downy hairs. 

 Within five days after the hatching the 

 larvae become a creamy white, which color 

 is retained until maturity. 

 The mature larvae (fig. 3) are 6 to 8 mm. in length and about 2 mm. 

 in diameter. The head is slightly smaller than the thorax, the body 

 becoming a little larger toward the anal extremity. The thoracic 

 segments bear stout legs, and beginning with the second abdominal 

 segment the next seven segments each bear a pair of ambulatory pro- 

 cesses (fig. 3, a) which terminate in a long hair, accompanied by four 

 shorter hairs. The anal plate (fig. 3, o) consists of five parts, which 

 are very characteristic of this species and form 

 a character which separates it from all other 

 larvae of the Eumolpini group. 



During the last six years the writer and 

 other members of the Bureau of Entomology 

 have been making efforts to rear the larvae of 

 this species from egg to maturity, in order to 

 determine definitely its food plant and exact 

 life history. In the laboratory almost every 

 form of receptacle has been used that could 

 be devised, from a tiny -vial with several 

 kinds of food in it, fitted with blotting paper 

 to absorb undue moisture, to flowerpots buried 

 in the soil, which it was thought might simu- 

 late more natural conditions. 



The list of growing plants involved in these experiments is as follows : 

 Cocklebur (Xantliium spinosum), smartweed (Persicaria liydropiper), 

 Japan clover (Lespedeza striata), crab grass (Syntherisma sanguinale) , 

 sorghum (Sorghum vulgare), alfalfa (Medicago sativa), cotton (Gossy- 

 pium sp.), corn (Zea mays), wheat (Triticum vulgare), bluegrass (Poa 

 pratensis), pigweed (Chenopodium sp.), and barnyard grass (Ecliino- 



Fig. 3.— The southern corn leaf- 

 beetle: Larva, a, Ambulatory 

 process; b, anal plate. (Original.). 



