88 



INJURIOUS INSECTS 



naeus), which indeed it very closely resembles, having the 

 same series of orange-colored spots on each side of the 

 ahdomen. The gray and black markings, however, of 

 the wings diifer percejDtibly in the two species; and in 

 the Tobacco-worm moth there is always a more or less 

 faint white spot or d-ot near the centre of the front wing, 

 which is never met with in the other species. In Con- 

 necticnt and other J^orthern States where Tobacco is 

 grown, the Potato-worm often feeds n|)on the leaves of 

 the Tobacco plant, the trne Tobacco-worm being unknown 

 in those latitudes. In the more southerly States, on the 



other hand, and in Mex- 

 ico and the West In- 

 dies, the true Potato- 

 worm is unknown, and it 

 is the Tobacco-worm that 

 59.— POTATO- woKM, WITH PAEA- tlic tobacco gTowcrs have 



to fight. While in the 

 intermediate country both species may frequently be 

 captured on the wing m the same garden and upon the 

 same evening. In other words, the Potato-worm is a 

 northern species, the Tobacco- worm a southern species; 

 but on the confines of the two districts exclusively 

 inhabited by each, they intermingle in varying propor- 

 tions, according to the latitude. 



Eemedies. — :The larva is so voracious that it soon 

 makes its presence known by the bare stems, and by the 

 abundant droppings found upon the ground, and should 

 be sought for and destroyed. It has more than one in- 

 sect enemy, notably a fly, the larva of which, after 

 making its growth within the Potato-worm, comes to 

 the surface and spins a smooth white cocoon. Some- 

 times a very thin and feeble worm will be found with its 

 back covered with these cocoons, as in fig. 59. Such, 

 when found, should not be killed, as it is desirable to 

 propagate the fly, and the worm will never perfect itself, 



