22 



THE AMERICAN ENTOMOLOGIST. 



tenderer stems of the potato, while two of them 

 burrow, like a borer, exclusively in the larger 

 stalks ? Finally that almost every one of these 

 ten species has its peculiar insect enemies ; and 

 that a mode of attack, which will prove very 

 successful against one, two, or thi-ee of them, 

 will often turn out to be utterly worthless, 

 when employed against the remainder? 



We propose, in this article, in order to throw 

 some light upon a subject which appears to be 

 very generally enveloped in the dark clouds of 

 entomological ignorance, — to give a short ac- 

 count, illustrated by figures, of the above ten 

 foes of the potato. After this, if any Editor, 

 whether of a political or an agricultural journal, 

 shall persist in talking about " THE Potato 

 Bug," we shall have to turn him over to the 

 grammarians for deserved castigation, as an in- 

 veterate and incorrigible abuser of the defi- 

 nite article. 



[Kg- U.] 



Colors— (1) grayieh brown; (2) livid brown and white. 



TheStalkBoeek (Qortynanitela,Guenee) . — 

 This larva (Fig. 11, 2) commonly burrows in the 

 large stalks of the potato ; but is not peculiar to 

 that plant, as it occurs also in the stalks of the 

 tomato, and in those of the dahlia and aster and 

 other garden flowers. We have likewise found 

 it boring through the cob of growing Indian 

 corn, and strangely confining itself to that por- 

 tion of the ear ; and we formerly received a sin- 

 gle specimen embedded in the stem of Indian 

 com, from which we subsequently bred the 

 winged insect. By way of compensation, we 

 suppose, it is particularly partial to the stem of 

 the conunou cocklebur (Xanthium strumari- 

 um) ; and if it would only confine itself to such 

 noxious weeds as this, it might be considered as 

 a friend instead of an enemy. In 1868 it has 

 been more numerous than usual, and we noticed 

 it to be particularly abundant along the Iron 

 Mountain and Pacific roads in Missouri. In the 

 fore part of July, 1868, we ascertained that a po- 

 tato patch on land belonging to Mr. D. B. Wier 

 of Lacon, 111., had about every tenth stem oc- 

 cupied by this borer. The common Spindle 

 worm {Qortyna zece, Harris) , found burrowing 

 in the heart of young Indian corn, is a distinct 

 but allied species, pi-oducing an cntii-ely difier- 

 eut moth. 



The larva of the Stalk Borer moth leaves 

 the stalk in which it has burrowed about the 

 latter part of July, and descends a little below 

 the surface of the earth, where in about three 

 days it changes into the pupa or chrysalis state. 

 The winged insect (Fig. 11, 1), which belongs to 

 the same extensive group of moths {Noctua 

 family, or owlet moths) to which all the cut- 

 worm moths appertain, emerges from under 

 ground from the end of August to the middle of 

 September. Hence it is evident that some few, 

 at all events, of the female moths must live 

 through the winter in obscure holes and cor- 

 ners, and lay their eggs upon the plants which 

 they infest in the following spring. For 

 otherwise, as there are no young potato or to- 

 mato plants, or Indian corn, or dahlias, or ^ 

 asters, or even cocklebur for them to lay their 

 eggs upon in the autumn, the whole breed of 

 them would die out in a single year. 



This insect has long been known to en- 

 tomologists in the moth state, although until 

 the year 1867 nothing had been printed res- 

 pecting its lai-val history. The junior editor 

 of tliis journal was the first to publish an 

 accurate Mstory of the species in all the 

 stages, together with a full description of the 

 larva, which will be found in the Prairie Far- 

 mer for February 23d, 1867. 



[Fig. 12.] 



Colors— (o and 6) white; (c) ash gi'ay and black. 



The Potato-stalk "Weevtl (Baridius trino- 

 tatuSySnj). — This insect is more peculiarly a 

 southern species, occrrrring abundantly in the 

 Middle States and in the more southerly parts of 

 Indiana and Illinois, and also in Missouri ; but, 

 according to Dr. Harris, being totally unknown 

 in New England. The female beetle (Fig. 12, c) 

 deposits a single egg in an oblong slit about one- 

 eighth inch long, which it has previously foi-med 

 with its beak in the stalk of the potato. The 

 larva subsequently hatches out, and bores into 

 the heart of the stalk, always, according to Miss 

 Morris of Pennsylvania, who was the first to 

 notice it, j)roceeding downwards towards the 

 root. Wlien full grown, it is a little over one; 

 fourth inch long (Fig. 12, a), and is a soft whit^ 

 ish, legless grub, with a scaly head. Hence it 

 can always be readily distinguished fi-om the 

 larva of the Stalk Borer, which has invaria- 



