602 Membrdcis, Coccidce, 



To these we here add, from the Encydojpcedia of Garden-- 

 ing, now being published, 



Figures of Three Species of Membrdcis. {fg.6S.) — aa^ 

 M. ensata ; b, M. fuscata ; c, M. spinosa. The appendages, 

 unusual to insects generally, which give 

 these creatures so striking a form, are, 

 according to Kirby and Spence [Introd.^ 

 ed. 1827, iii. 537.)5 processes of the pro- 

 thorax. See the Introd, of these authors, 

 in ii. 225., iii. 537., for notices of various 

 species of insects remarkable for their 

 exterior form, armature, or vesture. In 

 the ILncyclopcedia of Gardenings J 3071., 

 it is stated, from Mr. Swainson, that he 

 has " never met with the A'phides in 

 South America ; but that their place in 

 nature is there supplied by numerous species of Mem- 

 bracis [see fig. 68.], Centrotus [see figures and descrip- 

 tions of six species in II. 20 — 22.], &c., which are, in fact, 

 the plant-lice of that continent." This last remark advises 

 us, in a general way, of the habits of these creatures ; and 

 this may be learned more particularly by a perusal of the 

 communications on Z)elphax saccharivora JVestwood, by our 

 Grenada correspondent and Mr. Westwood, in VI. 407. 409., 

 VII. 496., as the genera Z)elph ax and Centrotus are allied ones ; 

 and the genera Centrotus and Membracis are so closely allied, 

 that some of the species of them have been interchanged. 

 The Centrotus cornutus and genistae of Curtis's Guide 

 (1829), two British species, are the Membracis corniata and 

 genistae of Samouelle's Entomologist^ s Co?npe?idium (1824). 

 It must he interesting to learn, by a comparison of the Bri- 

 tish species with the figures of American ones, in what degree 

 their forms assimilate or differ. Centrotus genistae is, accord- 

 ing to Mr. Curtis's Guide^ figured in his British Entomology^ 

 t.313. 



The Coccidce of the West Indies^ exclusive of insects there 

 of the affinities just remarked on, are, it seems, agents there 

 of the same effects in the economy of nature, as the aphides 

 are in Europe. Mr. Guilding had remarked, in a note rela- 

 tive to the mention, in II. 104., of aphides on the roots of 

 plants of endive and lettuce in England, that " We have 

 several of the Coccidae attached to the loose roots of plants, 

 which soon die or droop from their attacks." 



Nearly all, it may be said quite all, collections of tropical 

 plants cultivated in Europe are attended by a species of 

 coccus, which English gardeners have named the scale. 



