THE ORTHOPTERA OF MINNESOTA. 4-5 



ing every where for the eggs of locusts. If an egg-pod has 

 been found, the larva forces its way into it and commences 

 to devour an Ggg; if two larvae have found the same prize a 

 mortal combat takes place, lasting until a single larva re- 

 mains as sole owner of this store of food. As soon as one 

 or two eggs have been consumed the larva throws off its 

 skin, and reappears in a very different shape, being now 

 white, soft, and possessing only small legs. In the course of 

 another week a second molt takes place, disclosing a larva 

 with rudimentary mouth-parts and legs, and of a verv 

 clumsy aspect. Soon another molt takes place, but only 

 slight changes are seen in this form of the larva. After eat- 

 ing the remaining eggs in the pod, and leaving it, it bur- 

 rows in the soil, where it forms a smooth cavitv, within 

 which it rests. Soon it splits its skin again, disclosing now 

 quite rudimentary, tuberculous mouth-parts and legs; the 

 semi-pupa thus formed is rigid and of a deeper yellow color. 

 It hibernates in this condition. In spring the skin is again 

 torn open, and a larva appears looking like that of the 

 second shape, but smaller and whiter; it is quite active, but 

 does not seem to require any food. It changes into a true 

 pupa, and eventually into a winged beetle. 



Besides these species still another one with bright 

 metallic colors, the Cantharis Nuttalli, is exceedingly abund- 

 ant in years following locust troubles. Very likely the larva 

 of this beetle possess similar habits, and are consequentlv 

 very beneficial. 



OTHER PARASITES AND CANNIBALS. 



Quite a number of eggs of the locusts are destroyed by 

 othertrue parasitic insects, one o( which is illustrated in Fig. 

 17. It is called Scelio Luggeri, Ril. In some egg-pods every 

 ^S& is eaten by the larvae of this useful insect, so that instead 

 of harboring the embryo of a locust the tgg contains a small 

 wasp. These minute insects are difficult to find, as they are 

 not distinguished by metallic colors, which is usually the case 



