26 



THE AMERICAN ENTOMOLOGIST. 



The TniiEE-LiNED Lkai'-beetle (Lenia tri- 

 lineata, Olivier). — The three first insects, 

 described aud figured above as infesting the 

 potato-plant, attack it only in the larva state. 

 The four next, namely the four Blister-beetles, 

 attack it exclusively in the perfect state. The 

 three that remain to be considered attack it both 

 in the lai-va and in the perfect state, but go 

 underground to pass into the pupa state; in 

 which state — like all other Beetles, without ex- 

 ception — they are quiescent, and eat nothing at 

 all. 



The larva of the Three-lined Leaf-beetle may 

 be distinguished from all other insects that prey 

 upon the potato by its habit of covering itself 

 with its own excrement. In Figure 16 a, this 

 larva is shown in profile, botli full and half grown, 

 covered with the soft, greenish exoreraentitious 

 matter wliich from time to time it discharges. 

 Fig. 16 c gives a somewhat magnified view of 

 the pupa ; aud Fig. 16 b shows the last few joints 



nomcuolatare is getting to be an imbearable nuisance, and 

 must be iiiit astoi) to. Otberwisc one-hiilf of the time of 



stiiilyini,' "Uf sri.iitiiic, phrases. \Vr iir..|"i.-i', therefore, at 

 the wry next session of Coiifiress, to procure thi- passage of 

 a law, which shall inflict a fine of $li)(iu upon every entomo- 

 logieul writer who willfully, causelessly, maliciously, and 

 without any practical benefit tliereby reUnuntlin^^ to science, 

 shall ilisturb the established nonienclarure of any insects, 

 commonly called bugs; $999 of the aforesaid $1000 to be 

 always paid into the fiscal chest of the Amekicajj Entomo- 

 logist, and thi- remaining $1, after deducting legal expenses 

 and all the customary pickings and steel-filings, to be appro- 

 priated to the payment of the National debt. 



Many writers, in giving the scientific designation of an 

 insect, neglect to add the name of the author %vho first 



ribe 



oftel 



Whereas, if we add the aulhor's name, all -ImuM- ui.nn i|,e 



those wearisome and interminable disputes about the priority 

 of names and the law of priority, which take up so much 

 space in scientific papers, while they add absolutely nothing 

 to fuir knowledge of the facts recorded by the finger of God 

 in the great book of Nature. 



of the abdomen of the larva, magnified, and 

 viewed, not in pi-ofile, but from above. The 

 vent of the lai-va, as will be seen fi-om this last 

 figure, is situated on the upper surface of the last 

 joint, so that its excrement naturally falls upon 

 its back, and by successive discharges is pushed 

 forward towards its head, till the whole upper 

 surface of the insect is covered with it. In other 

 insects, which do not indulge in this singular 

 practice, the vent is situated either at the ex- 

 . treme tip of the abdomen or on its lower surface. 

 There are several other larvae, feeding upon 

 other plants, wliich commonly wear cloaks of 

 this strange material, among wlvieh may be 

 mentioned one which is very common upon the 

 Sumach, and which produces a jumping, oval 

 Leaf-beetle {Blepharida rhois, Foerster) , about 

 a quarter of an inch long, and of a yellow color, 

 speckled with brick-red. The larvas of certain 

 Tortoise-beetles (Cassida), some of wliich feed 

 on the Morning Glorj' and the S^VQet Potato 

 vines, adopt the same inacticc-, luit in 11i('ir case 

 there is a fork (•' I ].r."c.~, at the lail which curves 

 over their backs and i-ccci\cs llic i'c(|uisite sup- 

 ply of excrement. The ditt'ercnce between the 

 two modes adopted by these two groups of 

 lai-viP may be compared to the difference between 

 two savages, one of whom struts about with an 

 armful of manure on the top of his head, wliile 

 the other one, having become more delicate and 

 refined iu his notions, holds up a forkful of 

 manure, by way of parasol, over Iris head, as he 

 displays his chai-ms to the admiring world. 



Many authors have supposed that the object of 

 the larva, in all these cases, is to protect its soft 

 aud tender body from the heat of the sun. This 

 can scarcely be the correct explanation, because 

 then they would throw away their parasols in 

 cold cloudy weather, which they do not do. In 

 all probability, the real aim of Nature, in the 

 case of all these lai-voe, is to defend them from 

 the attacks of birds and of cannibal and parasitic 

 insects. 



There are two broods of this species every 

 year. The first brood of larvw may be found on 

 the potato vine towards the latter end of June, 

 and the second iu August. The Ihst In-ddd stays 

 underground about a fortnight Ijelure it emerges 

 in tlie perfect Beetle state ; and the second brood 

 stays there all vsdnter, and only emerges at the 

 beginning of the following June. The perfect 

 [Fig. 17.] Beetle (Fig. 17.) is of a pale yellow 

 color, with three black [Fig. is.: 

 stripes on its back, and 

 bears a general resem- 

 blance to the common Cu- 

 c 1 1 1 n I M • r-bug {Diabroticu, 

 filliita, Fabr., Fig. 18.) 



ulors-I'ale vel- , . , . Colors- Yell<i 



low aud blaci. From this last species, andWack. 



