No. 7. DEPARTMENT OP AGRICULTURE. 311 



beetles. They are used for medicine, as the blister beetle or Span- 

 ish fly, from which is obtained the tincture of cantharides. They 

 are also effective in preventing disease, as the dragon fly, which cap- 

 tures and kills mosquitoes, and thus prevents the spread of ma- 

 laria, w'hich is carried by the latter insects. 



Insects produce food directly, as does the honey-bee, and indi- 

 rectly by fertilizing flowers of various kinds, as do the bees, wasps, 

 flies, butterflies, moths, beetles, etc. They also produce food in an 

 indirect way (2) by becoming the food of fishes, frogs, edible fowls 

 etc., and especially by fertilizing our fruits. 



The chief way in which insects are beneficial is by preventing the 

 loss of the property of men, and this they do mostly by preying upon 

 destructive insects. Among those that are predaceous are the 

 mantis, assassin-bug and many other true bugs (Hemiptera); lace- 

 wing fly, ant-lion, various beetles, especially the lady-beetles and 

 ground beetles or caterpillar hunters, robber flies, certain wasps, 

 hornets and others. These insects should be recognized and pro- 

 tected whenever possible because they aid in suppressing the out- 

 breaks of those species that are most injurious. The best way 

 to learn to know them is to see the specimens themselves. Submit 

 material to entomologists for identification and obtain informa- 

 tion concerning the same. All questions upon such subjects will 

 be answered cheerfully and freely by the speaker. 



Among the most beneficial of insects are those that are called 

 parasitic. The predaceous insects might be called external para- 

 sites, while those to which we refer at present are called internal 

 parasites. Among these are various kinds of flies, such as the 

 tachina fly, minute wasp-like insects such as the Braconids, and 

 larger wasp-like insects like the Ichneumon flies. These have been 

 so beneficial at certain times when there were severe outbreaks of 

 injurious insects, that they were almost the sole factors in sup- 

 pressing such outbreaks. Three years ago, when the stinking 

 squash bug destroj-ed nearly all the squash, cucumbers and musk- 

 melons in certain parts of this State, we were asked if these pests 

 would be present another j^ear. In attempting to answer this quest- 

 tion, we examined many of the bugs in the fall and found, practically, 

 all of them attacked by internal parasites, chiefly the tachina fly.. 

 It is needless to say that the parasites did their work so well that in 

 accordance with our prediction the squash bugs did not appear the: 

 next year in destructive numbers, nor even the second year. 



It is not infrequent that entomologists, in keeping cocoons of moths 

 or chrysalids of butterflies over winter from which to obtain fine 

 specimens in the spring, find that instead of gorgeously colored 

 Lepidopterous insects emerging from their cages, they have small 

 brown wasp-like insects which have lived as parasites in the speci- 

 mens which they desired to obtain. These are Ichneumon flies, and 



