134 Indian Museum Notes. [Vol. V. 



On Dioscorea alata, Linn. Natural Order Dioscoreacece* 



The kham-alu. 



i. Crioceris impressa, Fabricius, Family Chrysomelidse. Plate 

 viii, Figs. 6 and 6 a, imago twice enlarged. 



The larva of this beetle was found in Calcutta in August, 1901, 

 feeding on the leaves of the native vegetable kham-alu. On breeding 

 them it was found that the species is Crioceris impressa, Fabricius, 

 which is represented in the Museum collection from Maldah, Calcutta, 

 Sikkim, Sibsagar, and the Andaman Isles. 



V.-INSECT PESTS OF CEREALS AND CROPS. 



On Brassica sp, 9 Natural Order Cruciferce. The mustard plant. 



i. Syrphus sp., Family Syrphidse, Order Diptera. 

 Mr. J. D. Cargill, I.C.S., Officiating Collector of Noakhali, 

 forwarded to the Indian Museum through the Director of Land Records 

 and Agriculture, some pupae of a fly locally known as " gunipoka", 

 which was said to destroy the mustard crop in the Noakhali district 

 in January. On breeding out the perfect insects they were found to 

 comprise three species of the dipterous genus Syrphus, Family 

 Syrphidse. The genus is a very large one, some two thousand spe- 

 cies being known, and as but few Indian species have been described, 

 it is not possible to name the specimens under consideration more 

 closely. A large number of the species of Syrphus feed on plant- 

 lice [aphides), and as numerous specimens of these insects were 

 present on the mustard sent by Mr. Cargill, it is almost certain that 

 the Syrphus larva feed on the aphides, so instead of being a pest 

 they are beneficial to agricuiture. No species of Syrphus is known 

 to eat living vegetable matter. 



On Sesatnum indicani, D.C., Natural Order Pedalinew. Til or 



sesamum. 



i. Aphanus sordidus, Fabricius. Sub-family Aphaninae. Family 

 Lyg&idae. Sub-order Heteroptcra. Order Hemiptera. 



Mr. A. E. Lawrie, Deputy Conservator of Forests, Chanda, 

 Central Provinces, sent on 22nd February, igoi, some bugs to the 



