List of the Insect Fauna of the County. 113 



Gall-makers are found amongst two families of the highly 

 specialised Hymenoptera. A few sawflies (Tenthredinidsej 

 produce galls, but it is to the allied family Cynipidas that the 

 gall-flies par excellence belong. The life-history of the Cyni- 

 pidaB is somewhat varied. It contains parasites (true mur- 

 derers), inquilines (true burglars), and gall-makers (true 

 house-holders). 



The study of the imagos will be found somewhat puzzling 

 to the general entomologist, as there is a very general like- 

 ness amongst the species ; and even the cuckoo gall-flies, or 

 Synergi, which are inquilines (lodgers in galls), greatly 

 resemble the true gall-producers. In several instances Linne ^^ 

 and other systematistshave taken the one for the other. Other 

 genera of Cynipidae are parasitic on the Siricidas, on various 

 Diptera, and on plant-lice (Aphides) ; but it is with the gall- 

 making species only we are just now concerned. I will, how- 

 ever, take this opportunity of warning the student how 



'5 Of the 19 species of Cynips described by Linne (Syst. Nat.), 7 only 

 are true gall-makers, the other twelve being either inquilines or parasites. 

 Fabricius noticed 23 species of Cynips; many are referable to gall- 

 makers of other orders than Hymenoptera, and there the inquilines, para- 

 sites, and gall-makers are equally confused. Neither of these great 

 masters of Entomology referred to Malpighi's remarkably accurate de- 

 scriptions and figures in his ' De Gallis ' (1686). 



This note reminds me of a distinguished Essex gall observer, Eev. W. 

 Derham, D.D., F.E.S., &c.. Canon of Windsor, and for many years Rector 

 of Upminster, in this county. In his * Physico-Theology,' altogether a 

 remarkable series of sermons, or Boyle lectures (1711 and 1712), there 

 is much curious information about our Essex gall fauna. Part of one 

 note runs thus : — " Since my penning this I have met with the most 

 sagacious Malpighi's Account of Galls, &c., and iind his Descriptions to 

 be exceedingly accurate and true, having traced myself many of the 

 Productions he hath mentioned. But I find Italy and Sicily (his Book 

 De Gallis being published after he was made Professor at Messina) more 

 luxuriant in such Productions than England, at least than the Parts about 

 Upminster (where I live) are. For many, if not most of those about us, 

 are taken Notice of by him, and several others besides that I never met 

 with ; although I have for many Years as critically observed all the 

 Excrescences, and other morbid Tumors of Vegetables, as is almost 



possible, and do believe that few of them have escaped me " — 



' Physico-Theology.' Tenth Ed., p. B8G, note z. (London, 1742), 



o 



