( 533 ) 



Transformations of a Carahid (Plodiioiiiis tiiimliis), and ob- 

 servations on a Coccinellid enemy of the red spider. 



By J. C. DuFFEY. 



(Presented October 20th, 1S90.) 



Among the many insect pests that damage the foliage of our 

 forest and shade trees, the fall web-worm (^Hyphantria atnea^ 

 Drury) is probably one of the worst. It not only destroys the 

 foliage, but covers the tree with its web, making a very ugly 

 sight. The great damage done by this insect gives us a special 

 interest in its enemies. Charles V. Riley mentions* the follow- 

 ing insect enemies of H. cH?ica: External — Alantis Carolina., 

 Prioniihis cristattis^ EncJiistus so'vus, and Poidesiis spiiiosics. 

 True parasites — Telcnomus bijidiis (an egg-parasite), Alctortts 

 hyphantrice., Apantcles Jiyphantrice^ Limneria pallipes., and 

 Tachiiia., sp. 



At the Missouri Botanical Garden, during the present season, 

 three other enemies of H. cunea have been observed : one of the 

 jumping spiders (Aranidce), the larva of a lace-wing fly {Chry- 

 sopa) feeding on both eggs and larvse, and a beetle, Ploch'ioims 

 timidiis., Hald. The life-history of the latter is of interest not 

 only on account of its preying upon one of our worst tree- 

 defoliators, but also as the life-history of no species in this genus 

 has hitherto been described, while it has been traced for compa- 

 ratively few of the Carabid beetles. 



June 9, webs of Hvphantria cunea began to appear on various 

 trees in the Garden. One of the colonies was given to one of 

 the garden pupils, Mr. James Dunford, with instructions to rear 

 the insects. Mr. Dunford soon found that the larvce were disap- 

 pearing, and, on examining the web, discovered several small 

 black larvae of some unrecognized Carabid, which were evidently 

 the cause of the trouble, and afterward proved to be Plochionus 



* Report of Entomologist, U. S. Dept. Agr. for the year 1SS6. Reprinted in Bull. No. 

 10, Div. Entomology, 1SS7. 



