534 TRANS. ST. LOUIS ACAD. SCIENCE. 



timidus. Other webs were then examined for this insect, and 

 from two to twenty larvse were found in nearly every web, where 

 they were also observed feeding on the larvae of H. cunea. In 

 many webs the Hyphantria larva; were greatly diminished in 

 numbers, and occasionally a web was found entirely uninhab- 

 ited. On the 24th of June, a web of H. ainea was found in 

 which were only 18 larvae of the web-worm, but which contained 

 an equal number of the predaceous larvae. June 35, seven-tenths 

 of all webs found contained larvae oi P. tiviidits. June 28, very 

 few webs of H. cimca were found, and most of them were unin- 

 habited. Where the web-worms were found, the larvae of P. 

 timidus were also invariably present. By July i, the Uyphajt- 

 tria larvae had disappeared. 



Two beetles of P. ti7nidus were found in a web of H. cunea 

 in the breeding-cage on July 7th, and one flew into Mr. Dun- 

 ford's window on the evening of July 31st, probably attracted by 

 the light. 



The second brood of web-worms began to appear July 22d. 

 On the 5th of August, adults oi P. timidus were observed in the 

 webs, and new larvie of this species were found three days later. 

 Aug. 6, forty-eight webs were cut from mulberry-trees and care- 

 fully examined. Besides the Hyphantria larvae, the following 

 insects were found : P. timidus^ 8 beetles and 7 larvte ; 7 Chry- 

 sopa larvas ; 5 spiders ; and i adult Coccinellid. 



A careful search was made about this time for the eggs of /Vo- 

 chiomis. Aug. 11, Mr. Dunford found, in a web of//. c7tnca. a 

 small white foreign egg. Having seen one, it was not difficult 

 to find others, and thirty-two eggs were found in the portion of a 

 web covering a single mulberry leaf. Aug. iS, other eggs of P. 

 timidus were found in a web of H. cu/iea. These eggs must 

 have been laid several days after the hatching of the Hyphantria 

 eggs, as they were distributed through a portion of the web cov- 

 ering several mulberry leaves, and the Hyphantria larvae must 

 have been feeding for some time to have extended their web so 

 far. Aug. 29th, half-grown larvae, fall -grown larvte, and the 

 imago oi P. timidus were found in Hyphantria webs. The last 

 Plochioiius larva found in a web was discovered Sept. 4. This 

 larva pupated Sept. 11, and on the 24th had assumed the form of 



