25S 



THE AMEEICAN 



the clay, hovering, humming-bird-fasMon, over 

 verbenas and other flowers. The larva feeds 

 upon purslane, turnip, buckwheat, watermelon, 

 and even apple leaves, upon any of which it may 

 be found in the month of July. It descends into 

 the ground and, witliin a smootli cavity, clianges 

 to a light brown chiysalis, from which the moth 

 emerges during the month of September. 



The most common form of this lai-va is that 

 given at Figure 163 ; its color is j'ellowish-green, 

 with a prominent subdorsal row of elliptical 

 spots, each spot consisting of two curved black 

 lines, enclosing superiorly a bright crimson space, 

 and inferiorly a pale yellow Une — the whole row 

 of spots connected by a x^ale yellow stripe, edged 

 above with black. In some specimens these 

 ej^e-like si^ots are disconnected, and the space 

 between the black crescents is of a uniform 

 cream-yellow. The breathing-holes are either 

 surrounded with black, or with black edged with 

 yellow. The other form is black, and character- 



trig, itii ] 



Colors— Black, orange aud j'i-,llo\v. 



ized chiefly by a yellow line along the back, and 

 a series of pale yellow spots and darker yellow 

 dots, as reiDresentedin our illustration (Fig. 1C4) . 

 Even this dark form is svibject to great variation, 

 some specimens entirely lacking the line along 

 the back, and having the spots of different shape. 

 This insect has a wide range, as it occurs in 

 the West Indies, Mexico and Canada, as well as 

 throughout the United States. Feeding as it 

 does principally on plants of but little value, and 

 being very commonly attacked by the larva of a 

 Tachiua-fly, tliis insect has never become snffi- 

 ciently common to be classed as injurious. 



DESCRIPTIVE ENTOMOLOGY. 



In a paper on the larval history of certain 

 moths, from the pen of that earnest entomolo- 

 gist, J. A. Lintner, of Albany, N. Y.., the fol- 

 lowing passage occurs : 



Every faithful student will welcome each con- 

 tribution, however trivial, which shall hasten 

 the day when of each insect the egg, the larva, 

 the pupa, and the imago, or perfect form, shall 

 all be known, described aud flgured, and the 

 discovery of a new species, however microscopi- 

 caily minute it may be, shall be a triumph.* 



*Pi-oc. Eut Soc. rhil., Ill, p. G45. 



Tins is a noble burst of entomological enthu- 

 siasm ; but let us pause here for a moment and 

 make a few calculations as to the probability of 

 a consummation so devoutly to be wished ever 

 being achieved. It is usually estimated that in 

 the whole extent of this terrestrial globe, there 

 exist about half a million distinct species of 

 insects. We strongly incline to believe that, 

 even if we double this nmnber, we shall still be 

 rather under than above the correct estimate. 

 Nevertheless, to be on the safe side — for we 

 always dislike to overstate a case — we will con- 

 sider the customary estimate as a tolerably near 

 ai^proximatiou to the truth. Let us suppose 

 now that Mr. Lintner's idea is about to be car- 

 ried into practical effect, and let us ask ourselves 

 the following three questions : 



1st. How much space upon our bookshelves 

 Avill a work occupy, which describes and figures 

 every insect in the world in each of its four 

 stages? 



2nd. How much time will 

 it take to write such a work, 

 and how much to execute 

 the requisite drawings ? 



3rd. Wliat will be the cost, 

 in dollars and cents, of print- 

 ing, say 10,000 copies of such 

 a work, and of executing 

 the requisite colored draw- 

 ings and colored engravings to illustrate half a 

 million insects in their four distinct stages? 



Sux)posc we consider these three questions in 

 the order in which they stand, numbering the 

 answer to each, so as to correspond with the 

 question itself. 



1st. It will be allowed by every one, who has 

 had much exjierience in such matters, that the 

 four stages of an average insect cannot be accu- 

 rately and satisfactorily described in less than 

 one octavo page of ordinary brevier or bourgeois 

 type. We should be inclined to double tliis 

 estimate, but we are determined not to overstate 

 the case. The illustrations of an insect in its 

 four stages — considering that there are many 

 insects so large in the jierfect or winged state 

 as to cover the whole surface of an octavo page, 

 and considering further, that even such as are 

 exceedingly small must be considerably magni- 

 fied by the artist, in order that the drawing may 

 be worth anything at all — will certainly occupy 

 one-fourth of an octavo page. Thus, as an aver- 

 age insect will occupy 1 i octavo pages, it results 

 that, to describe and illustrate 500 insects will 

 requii'c G2.5 octavo pages, wliich is about the 

 number of pages contained in one stout octavo 

 volume. Moreover, it ftirther follows, that to 



