19141 Brijant: Economic Status of the Western Mcadoirlark 4:^5 



DlPTERA 



Eristalis tenax Lucjlia caesar L. 



Tachina sp. Miisoa sp. 



Syrphus sp. ? Tipula sp. 



Quantity destroyed. — Flies do not constitute any important 

 percentage (about one per cent) of the food for the year and 

 when found have been in small numbers. A few green bottle- 

 flies and other members of the same family are eaten, as are also 

 flower-flies and drone-flies. Birds collected at El Toro, Orange 

 County, during 1911 had eaten large numbers of the pupae of 

 flower-flies {ISyrphits sp.). Crane-flies {Tipula sp.) are not taken 

 as often as it would seem they would be from their abundance. 

 Evidence is at hand, however, that western meadowlarks feed 

 largely on the larvae when they become abundant. ]\Ir. W. M. 

 Hughes of Madera, Madera County, has made the following 

 report: "When I visited the tract of land affected, I found 

 myriads of blackbirds and thousands of meadowlarks on the 

 ground making small holes into the ground at the roots of the 

 plants and taking out the w'orm. Several hundred acres of fine 

 crop was destroyed before the birds collected in numbers suffi- 

 cient to destroy the pest." The outbreak referred to was in the 

 vicinity of Minturn, Madera County, in 1909. Several hundred 

 acres of barley were destroyed by crane-fly larvae at this time. 



Economic importance. — In spite of the fact that the larvae 

 feed upon decaying matter, most flies are considered pests be- 

 cause some of them carry germs of disease. Green bottle-flies 

 are disease carriers. The larvae of flower-flies feed upon plant 

 lice and hence are considered beneficial. The lai-vae of crane- 

 flies, on the other hand, are destructive to vegetation. The small 

 numbers of flies taken and the fact that in.jurious as well as 

 beneficial forms are eaten make the destruction of Diptera by 

 meadowlarks of little consequence. 



Arachnida {Spiders) 



Quantity destroyed. — Spiders and their egg-cases form less 

 than one per cent of the food for the year. Most of the spiders 

 taken are grass spiders (Agalenidae) and daddy-long-legs (Pha- 



