3 8o 



ENTOMOLOGY 



nate plant lice locally. Weather conditions may render the plants 

 unfit for food, or may prevent the eggs from hatching. In short, 

 aphids are affected for good or ill by all the influences that act upon 

 their food plants. 



Enemies are abundant. Many kinds of spiders and a few kinds of 

 mites kill the lice. The English sparrow eats the pea louse voraciously, 

 and the chickadee in winter consumes enormous numbers of aphid eggs. 

 Most of the enemies are, however, other insects. Here are lists of the 

 insects known to affect, directly or indirectly, the common pea louse, 

 or clover louse, Macrosiphum pisi. 



PREDATORS 1 



CoccindlidcB (lady beetles) 

 Ceratomegilla fuscilabris 

 Hippodamia tredecimpunctata 

 Hippodamia parenthesis 

 Hippodamia glacialis 

 Hippodamia convergens 

 Coccinella novemnotata 

 Cycloneda sanguinea 

 Adalia bipunctata 

 Chilocorus bivulnerus 



Syrphidce (flower flies) 



Ocyptamus fuscipennis 

 Platychirus quadratus 

 Syrphus americanus 

 Syrphus ribesii 

 Allograpta obliqua 

 Mesogramma marginata 

 Mesogramma polita 

 Sph'aerophoria cylindrica 



IchneumonidcB (ichneumons) 

 Praon simulans 

 Trioxys cerasaphis 

 Aphidius fletcheri 



Chrysopida (lace-wings) 

 Chrysopa oculata 

 Chrysopa rufilabris 

 Chrysopa plorabunda 



Gryllidcs (tree-crickets) 

 (Ecanthus confluens 



PentatomidcB (stink bugs) 

 Podisus maculiventris 

 Euschistus variolarius 



Anthocoridiz (flower bugs) 

 Triphleps insidiosus 



Cantharida (cantharids) 

 Podabrus rugulosus 

 Podabrus tomentosus 



Itonidid (gall gnats) 



Aphidoletes meridionalis 



PARASITES 



Aphidius washingtonensis 



Aphidius rosae 

 Miscogasteridce (miscogasterids) 



Megorismus fletcheri 



The species of the preceding list feed directly on the pea louse. 

 Those of the following list affect the louse indirectly, by feeding on the 

 preceding species or on one another. 



1 Additional details in regard to all these insects will be found in Bull, 111. Agr. Exp. 

 Sta., No. 134, and Bull. U. S. Dept. Agr., No. 276. 



