THE SYRPHIDAE OF OHIO 



35 



active on dull days. But, given a warm bright day and fragrant mellifer- 

 ous flowers, and many species, especially of Syrphiiiac and /'j-/stalinaen\2iy 

 often be taken in a short time. In fact the great majority of species, so 

 far as we know, are dependent on honey and pollen for food. Some, how- 

 ever, as the Chilosini, Xy/ota, Chrysogaster, Neoascia, do not so much ap- 

 pear in the open about flowers, but are to be looked for among the foli- 

 age of low bushes, in damp ])laces, or in low meadowy woods. Species 

 of Mesogramina can sometimes be taken in large numbers by beatino- 

 grasses in woody meadows. 



It frequently happens that immense numbers of adults of one or sev- 

 eral species emerge at about the same time; and this is doubtless responsi- 

 ble for the records of "swarming" of species of Syrphidae. During the 

 first Spring days one finds them about flowers in very great numl)ers, 

 but the}- are said to swarm in the sunshine irrespective of feeding as an 

 object. 



W. D. Hunter, Canad. Ento. XXVIII, 99, reports observing a male 

 of Eristalis JJavipes sucking the substance of a small grasshopper, Chlocal- 

 tiis curtipcnnis which was held in its grasp after the manner of many of 

 the Asilidac. If this really indicates the predaceous habit, it is, so far as 

 I can determine, an isolated example of divergence from the feeding habit 

 mentioned above. 



METHODS OF NATURAL PROTECTION 

 If there are in nature such things as terrifying coloration and mimi- 

 cry, we have among Syrphidae some excellent examples. Perhaps seven- 

 ty-five per cent of these species, and a much greater percent of the individ- 

 uals commonly seen, more or less closely resemble the popular idea of a 

 wasp or bee; that is, they are brightly banded, transversely, with black 

 and yellow on the abdomen, or are thickly pilose with the same colors. 

 Resemblances in shape, also, are in a good many species very striking, 

 and important in increasing the effect of similarity. I have been inter- 

 ested in noticing how many people, when shown a collection of Syrphidae 

 or a live specimen, at once pronounce them "bees" or express the belief 

 that they can sting. Also in a class of elementary students in Iuitomolog_\- 

 the percentage who at first place their Syrphid specimens among the 

 Hymcnoptcra is very great. It is often rather difficult for one to tell 

 whether a specimen flying about flowers is a Syrphid or a Hymenopteron. 

 Now it is supposed that enemies of insects learn b}' experience to 

 avoid those forms which are provided with stings or are in other ways 

 distasteful or unpleasant to them. The more striking the recognition 

 mark of such forms, the fewer the number of individuals that will be sacri- 



