26 



THE AMERICAN ENTOMOLOGIST. 



Colors— Dull White. 



The Thbee-lined Leaf-beetle {Lema tri- 

 lineata, Olivier). — The three first insects, 

 described and 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 larva and in the perfect state, but go 

 underground to pass into the pupa state; in 

 which state — like all other Beetles, vdthout 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 

 laiTa is shown in profile, both full and half grown, 

 covered with the soft, gi'eenish excrementitious 

 matter which from time to time it discharges. 

 Fig. 16 c gives a somewhat magnified view of 

 the pupa ; and Fig. 16 6 shows the last few joints 



nomenclature is getting to Ije an unbearable nuisance, and 

 must be put a stop to. Otherwise one-half of the time of 

 every entomologist, which might be much better occupied 

 in studying out scientilic facts, will be fi'ittered away in 

 studying out scientific phrases. We propose, therefore, at 

 the very next session of Congress, to ijrocure the passage of 

 a law, which shall inflict a line of $1000 upon every entomo- 

 logical writer who willfully, causelessly, maliciously, and 

 without any practical benefit thereby redounding to science, 

 shall disturb the established nomenclature of .any insects, 

 commonly called bugs; $909 of the aforesaid $1000 to be 

 always paid into the fiscal chest of the Ajmebican Entomo- 

 logist, and the remaining $1, after deducting legal expenses 

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

 priated to the payment of the National debt. 



Many wi'iters, in giving the scientific designation of an 

 insect, neglect to add the name of the author who first 

 described it. This practice often leads to error, imcertaiuty, 

 and confusion, as the preceding example will at once show. 

 If, for instance, we write simply ^' Jjyita cinerea, ' ' how can 

 the reader tell whether we mean the species described under 

 that name by Foerster, or the very distinct species described 

 imder the very same name ' ' cinerea ' ' by Fabricius? 

 Whereas, if we add the author's name, all doubts upon the 

 subject are at once removed ; and we can snap oui- fingers at 

 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 our 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 profile, but from above. The 

 vent of the lai-va, as will be seen from tliis last 

 figure, is situated on the upper surface of the last 

 joint, so that its excrement naturally falls upon 

 its back, and b)'' 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 larvre, feeding upon 

 other plants, wliich commonly wear cloaks of 

 tliis strange material, among wliich may be 

 mentioned one wliich 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 larvae of certain 

 Tortoise-beetles (Cass-ida), some of which feed 

 on the Morning Glory and the Sweet Potato 

 vines, adopt the same practice, but in their case 

 there is a forked process at the tail wliieli curves 

 over their backs and receives the requisite sup- 

 ply of excrement. The diflerence between the 

 two modes adopted by these two groups of 

 larvsB 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, while 

 the othei'ione, having become more delicate and 

 refined in his notions, holds up a forkful of 

 manure, by way of parasol, over his 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 

 and tender body from the heat of the sun. Tliis 

 can scarcely be the correct explanation, because 

 then they would thi-ow away their parasols in 

 cold cloudy weather, wliich they do not do. In 

 all probability, the real aim of Nature, in the 

 case of all these larvas, 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 lai-vaj may be found on 

 the potato vine towards the latter end of June, 

 and the second in August. The first brood stays 

 underground about a fortnight before it emerges 

 in the perfect Beetle state ; and the second brood 

 stays there all winter, 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 [fik.w.j 

 strij)es on its back, and 

 bears a general i-esem- 

 blance to the common Cu- 

 cumber-bug {Diabrotica 

 vittata, Fabr., Fig. 18.) 

 "i^^imi^'-Fvom this last species, ''"^diilar 



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