6 BULLETIN 171, U. S. DEPARTMENT OF AGRICULTURE. 



that eat the roots of grass and other plants, were found in 64. Sev- 

 eral other species of the family nearly as harmful were identified. 

 The Colorado potato beetle was found in 2 stomachs, and both the 

 striped and spotted squash beetles were identified in others. 



Larvae of the Lampyridae or fireflies, which live in the ground 

 and so fall an easy prey to the robin, were found in several stomachs 

 to the extent of upward of a hundred in each. Several species of 

 weevils or snout beetles, including the two clover weevils (Phytono- 

 mus punctatus and Epiccerus imbricatus) , the corn weevil (Spheno- 

 phorus zece), and a number of others, were identified. In June, 

 1911, 10 stomachs of robins were collected in Utah in the region in- 

 fested by the newly imported alfalfa weevil (Phytonomus posticus) 

 and 6 were found to contain these weevils in varying quantities. In 

 all, the birds had taken IT adults and 195 larvae, which amounted 

 to an average of 35 per cent of the food of each. This shows how 

 readily birds avail themselves of a new kind of food. Beetles col- 

 lectively amount to 16.72 per cent, of which Carabidae make up 5 

 per cent and Scarabaeidae 5.48 per cent. Weevils or snout beetles 

 amount to 2.13 per cent, and all others 4.11 per cent. 



The robin evidently is not a lover of Hymenoptera (bees, wasps, 

 etc.) as the total consumption is only 2.60 per cent. Of these, 1.57 

 per cent are ants and the remainder, 1.03 per cent, wild bees and 

 wasps, except a few bits of a single worker honey bee {Apis mel- 

 lifera). This is in strong contrast to the food of birds of the genus 

 Ilylocichla, which consists on the average of over 12 per cent of ants. 

 It is evident that the robin does not care for ants; and as it is not 

 adept at capturing active creatures it is not surprising that it does 

 not eat many wasps or bees. 



Hemiptera (bugs) constitute only 2.20 per cent of the robin's food, 

 but are taken to some extent in every month. Februa^ and April 

 are the months of greatest consumption, with something over 5 per 

 cent in each ; March and May stand next with more than 3 per cent. 

 While eight families were identified, the Pentatomida? (stinkbugs) 

 greatly predominate. Probably the most interesting member of this 

 order eaten by the robin is the chinch bug (Blissus Zeucopterus) . 

 This injurious insect was found in two stomachs, and its presence 

 was suspected in several more. 



Diptera (flies) are represented in the food of the robin almost 

 entirely by larvae of the March flies (Bibionidae). Bihio albipennis, 

 the species most often eaten by robins, breeds in colonies in the 

 ground, feeding on grass roots. Naturally they are not found by the 

 birds so often as if they were more generally distributed, but when 

 found the whole colony is eaten. While several stomachs contained 

 less than 100 each of these larvae, at least 12 contained from 100 to 

 200; one contained 270, and another the remarkable number of 1,040. 



