186 THE ENTOMOLOGIST. 



be gregarious, yellow and haiiy, but of their nature I know 

 nothing. Any information you may be pleased to give will 

 be much esteemed. I fear the pest is very prevalent. — 

 A Farmer ; Wilton, July 28. 



(Having forwarded the preceding note to Mr. Newman, 

 whose communications on the subject of insects injurious to 

 vegetation have so frequently appeared in the columns of the 

 * Field,' that gentleman has sent us the following interesting 

 particulars. — Editor o/' Field!') 



The little caterpillars or grubs received from your corre- 

 spondent "A Farmer" are the larvae of the wheat midge, 

 known amongst us entomologists by the Latin name Ceci- 

 domyia Tritici. The fly which proceeds from the grub has 

 the appearance of a very small gnat, and is properly classed 

 with that familiar group of insects. Mr. Walker, the cele- 

 brated dipterist, has described no less than one hundred and 

 sixty-two British species of Cecidomyia, besides enumerating 

 about fifty others, the distinctive characters of which are not 

 clearly determined. Mr. Walker's labours consist prin- 

 cipally in translating, abridging, and connecting the diffuse 

 but highly elaborated descriptions of Winnertz and Loew, 

 especially the former, who observed the economy of many of 

 the species, while the latter has devoted his time and talents 

 more especially to describing the insects in their perfect 

 state. Most of the species in their larval or grub state feed 

 on living vegetables, often producing those galls and dis- 

 tortions which attract the notice of even the most unobservant ; 

 some live in decaying Fungi, several in the galls of the oak, 

 although I believe that none are known as the original 

 architects of any oak-gall or oak-apple ; they simply make a 

 home of the galls on the oak which other insects have 

 produced. Mr. Walker's monograph of the genus, com- 

 mencing at p. 77 of the third volume of his ' Diptera Britan- 

 nica,' exhibits an amount of learning, combined with personal 

 observation, that has rarely been equalled. Many of the 

 effects produced by the larvae or grubs of these little gnats 

 while feeding are familiar to us all, although the gnats them- 

 selves are so minute as to be sure to escape observation. 

 Cecidomyia rosaria forms very pretty rosettes on half a dozen 

 species of willow ; C. Salicis forms woody galls on the twigs 

 of Salix cinerea ; C. Papaveris lives in the seed-pods of the 



