MASON AND LEFROY. 37 



During an attack of the Castor Semi-looper (Ophiusa melicerte) 

 on Castor, 1909, these Crows fed to a certain extent on these cater- 

 pillars, but they were not present in large numbers and by no means 

 attacked the caterpillars so much as one would have expected. 

 Comparatively few birds were among the Castor and most were 

 feeding as usual in the fields and trees, some examined at the time 

 proving to have fed largely on Ficus, various insects, &c. The 

 stomach contents of the birds shot on this occasion are among the 

 records for 30-6-09. 



Other than these instances we have few in which it can be said 

 that crows are as beneficial as they could be. In fact they are not 

 generally b3neficial at all. If they eat injurious insects, it is only at 

 a time when these are in great numbers, a time when the damage 

 caused by these insects has been done and when the destruction of 

 thousands of these insects hardly makes any appreciable difference 

 in their numbers. I consider an attack on insects by birds under 

 these conditions as to all intents and purposes valueless : it can be 

 of very small value in comparison with the good done by some bird 

 which feeds habitually on injurious insects throughout the year and 

 which, therefore, is always checking undue proportion of that insect's 

 numbers. However actual and not comparative economic import- 

 ance is the point in question here. A crow only helps to lessen to a 

 small extent the undue proportion of any one species of insect, 

 when he notices they are in swarms and feels inclined to eat or 

 worry them. 



Crows have been said to feed on grubs (Hypera variabilis) on 

 Senji. They will feed on silkworm moths (Attacus ricini) while 

 alive, after being thrown away from the silk house. I once, at Pusa, 

 took numbers of silkworm eggs from some crows, but these were 

 almost certainly eaten together with the moths, the eggs not having 

 been laid. Mr. Finn remarks " though most which are at all 

 insectivorous with which I experimented, captive or wild, showed 

 more or less desire for butterflies, some would not eat them at all 

 crows (C. splendens) for instance." (A. S. B., LXVI, 667). The pre- 

 sence of the larvae of Laspeyresia jaculatrix, a Tortricid moth, was 



