48 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 85 



Nyssonidae, Mimesidae, and Crabronidae, among predacious hymen- 

 optera, prey more or less selectively upon Homoptera ; in the eastern 

 States a large Sphegid wasp is a special foe of cicadas. Other enemies 

 of cicadas include dragonflies, v^'asps, predatory beetles and bugs, 

 mantids, spiders, mites, hymenopterous and dipterous parasites, 

 fishes, snakes, turtles, squirrels, badgers, armadillos, skunks, moles, 

 and fungi. Spiders consume many Hemiptera of a wide variety and 

 are credited with being among the most important natural enemies of 

 leafhoppers. The latter insects are heavily parasitized by the Dry- 

 inidae, and by at least five other families of Hymenoptera, by Pipun- 

 culidae, and Strepsiptera ; and are preyed upon by larvae of Chryso- 

 pidae, and by Coccinellidae, Reduviidae, and certain other insects. 



The Pyrrhocoridae said to be specially protected are preyed upon 

 by spiders, pseudoscorpions, thrips (the eggs), tachinid flies, reduviid 

 bugs, and lizards. The Coreidae have special parasitic foes among the 

 Tachinidae ; while the order of Rhynchota in general is subject to 

 hymenopterous parasites, the abundance of plant lice and scale insects 

 in particular depending to a large degree in many cases upon the 

 relative numbers of these destructive foes. Lycaenid caterpillars feed 

 upon aphids, coccids, jassids, and membracids. A page would scarcely 

 suffice to list the numerous enemies of plant lice which include, besides 

 parasites, coccinellid, lampyrid, syrphid, hemerobiid, and chrysopid 

 larvae, in addition to adult ladybird beetles, assassin bugs, and other 

 insects, mites, and spiders. Fungi are known to destroy, at times, 

 large numbers of hemiptera, among which may be mentioned plant 

 lice, scale insects, mealybugs, and the chinch bug. 



Discussion. — Despite their malodorous secretions and other " pro- 

 tective devices " there can be no doubt that Rhynchota are taken fully 

 in proportion to their abundance by nearctic birds, and the evidence 

 is that their other enemies are numerous and effective. If we consider 

 the most pronouncedly repugnant species found in the United States, 

 such as the harlequin bug {Murgantia histrionica) and the squash bug 

 {Anasa tristis) ^ we find that severe infestations of the former have 

 been kept in check by English sparrows (Sherman, F., Bull. North 

 Carolina Dep. Agr., vol. 32, no. 7, p. 21, July, 191 1) and that the 

 squash bug has a number of deadly enemies. It has been shown that 

 the volatilized secretions of squash bugs if confined in a glass con- 

 tainer are capable of killing toads (Weed and Conradi, Bull. 89, New 



'It is worth noting that of these two common and exceedingly malodorous 

 bugs, one is warningly, one oI)scurely colored. Where is the correlation that 

 theories as to warning colors demand ? 



