572 INSECTA. 



majority of these insects are covered with a mealy matter, or with cottony threads, sometimes arranp:ed in rows. 

 The larva; of the Hemerobii, those of many Diptcra, and Coccinellit, destroy a great number of plant-Uce. W. 

 Aug'. Duvau has communicated to the Academy of Sciences the interestinff result of liis observations on tliuse 

 insects, and his memoir bas been inserted in the collection of those of the Museum dUIisL Nat. 



The Aphis of tlie oak (A. Quercus, Linn., lleaumur, 3, |»1. 28, f. 5), is remarkable for havin^^ the proboscis at 

 least tbree times as lono; as the entire body. 



M. Blot has published, in the Memoirs of the Liniuean Suricf// of Caen, 1S24, various curious observations upon 

 a species found in the Departement du Cuh'adny, w jncl] i.s very injurious to tlie apples, destroying the young; 

 shoots. He considers it as the type of a new «;cnn>, w hid] lie calls Mi/zo.ri/le. [It is proliable that tiiis insect is 

 identical with that so well known in Kiii^Iand under the name of Apple-blight, which i-s covered eidirely with a 

 white cottony secretion, and whicli nndtiplies in vast numbers in the crevices of the bark of diseased apple-trees. ] 

 De Geer also described a species of Aphis found upon the apple, but which dilTers materially from that described 

 by M. Blot, which last has no horns on the abdomen, the antenna; are shorter, and, according to M. Blot, only 

 5-jointed, the second joint beinij the longest. [The species of this family, Aphid;c, are extremely numeroup, 

 almost every plant possessing a distinct species. They however require a more minute investigation than has yet 

 been given to them. The Senator Van Heyden has described several new genera recently in the Memoirs of the 

 Museum Seckejihergeanum.] 



Alei/rodes, Latr. (T/Hca, Linn.), has tlie antennre short, r.-jointeil, and the eyes notrhed. T\7ie, T. p\-olei<lhty 

 Linn. ; Reaumur, Mdmoires, vol. ii. pi. 25, hg. 1 — 7, resembles a small white moth, having a small blackish spot 

 on each wing-cover. It is found on the leaves of the Chelidonium, cabbage, oak, &c. Its larva is oval, very flat- 

 tened, like a minute scale, and resembles tliat of Psylla. The pupa is fixed, and inclosed in an envelope, so that 

 this insect undei'goes a complete nietauioi-ijliosis. 



THE THIRD TAAilLY, OF THE IIOMOPTEROUS HEAH L'TERA,— 



The Gallinskcta, — 



Of ■wliicli Do Goer formed a distinct order, liave only a single jnint^'' in the tarsi, with a single book at 



the tip. The male is destitute of a proboscis, has only two \;ings, wliich shut hnrizontaliy upon tlie 



^ , body; the abdomen is terminated bv two tlirearls. The female is >\ithout wings, and 



3 -f?^ furnished with a proboscis. The autennrc are filifonn, or thread-like, and offen eleven- 



' jointed (nine in the species described by Dalman in the memoir noticed behj\v). These 



-^+ insects compose tlie genus 



Coccus, I.inn. (or Scale-insects). 

 Tbe hark of many of our trees appears often \^■art}", l)y i-eason of a great nuiiilicr of small 

 oval or rounded bodies, like a sliield or a scale, wliich are fixed to them, and in which no external 

 traces of the insect are to be observed. They nevertheless belong to this class of animals, and to the 

 genus Coccus. Some of these are females ; tbe others are young males, and which are similar to 

 them in form. But a period arrives when all these individuals undergo singular changes. They hx 

 themselves to the plant, the larvae of the males for a determinate period necessary for their trans- 

 formations, and the females permanently. If observed in spring, their bodies are noticed gradually to 

 increase in size, ending in their acquiring tbe apiicaraiicc of a gall, being either spbeiical, kiibicy- 

 sha-^ed, boat-shaped, Aic. Tlie skin in some is entire and very smoorb ; in others it is incised, or iillVrs 

 traces of segments. It is in this state that the females are impregnatcil, shortly after which they 

 deposit their eggs, of which tbe number is very great ; these they deposit between the ventral surface 

 of their bodies and a layer of a cottony secretion, with which they had [ircvioiisly lined the spot on 

 which they h.id stationed themselves. Their bodies subsequently dry up and become a solid cocoon, 

 which covers the eggs. Other females envelope their eggs in a very abundant cottony secretion, which 

 eciually defends them. Those wdiieh are of a spherical form become a kind of box, inclosing the eggs. 

 The young Scale-insects have the body oval, very flat, and furnished with the same organs as their 

 mother. They disperse themselves over the leaves, and reach by the end of the autumn the branches, 

 on which they affix themselves in order to pass the winter. Some, the females, prepare at the com- 

 meiieciuent of siirnuier to become parents ; and tbe otliers, or tbe larv;e of the males, are transl'ormcd 

 into piipK beneath their own skin. These ]iuprc have the two forc-feci directed forwards, and not 

 backwards, like the four hind legs, and like all the legs of the other inactive pupa:. Having acquired 



* L)ulj,ia,i, ill a iiiiMnolr vji,i.,[i some siieuii'S of Co^'cus, uousidtrs thiit tlic iiuivbcr of the joiiils io tlii.- tursi is tlirce. 



