ORTHOPTERA. 99 



tain lccust in the act of ovipositing. Certain species make holes with 

 their ovipositor in a similar manner in fence-rails, logs, stumps, and 

 other masses of wood, in which they deposit their eggs. After the 

 eggs are laid, the entrance to the hole in the wood is closed with a 

 little plug of gummy matter. 



The transformations of three of our more common species of 

 Melanoplus have been carefully studied by Riley.* These will serve 

 to illustrate the metamorphoses in this family. In each case there 

 are five nymph stages. In the first of these (Fig. 8), although the 

 insect would be readily recognized as a young locust, there is a 

 marked difference in the proportions of the body from those pre- 

 sented by the adult. This is especially noticeable in the large size 

 of the head, the relatively stouter thorax and hind femora, and in 

 the short abdomen. From this form to that of the adult there is 

 presented by the other nymph stages a very regular series of grada- 

 tions. The most striking change in the course of the development 

 of these insects is the growth of the organs of flight. In the first 

 nymph stage there is no indication whatever of wings ; in the 

 second stage the caudo-lateral angles of the mesonotum and meta- 

 notum are very slightly prolonged (Fig. 9). In the third stage these 

 prolongations are more marked, and are easily recognized as rudimen- 

 tary wing-pads (Fig. 10). In the fourth stage a remarkable change 

 has occurred in these organs : up to this point they have projected 

 downward and backward ; they are now turned up so that what was 

 their lower edges now meet on the narrow back, and the side of 

 each which was next to the body is now turned outward (Fig. 11). 

 While in this position the second pair of wing-pads is outside of the 

 first — the reverse of the relative positions of the fully developed 

 wings. In the fifth stage the wing-pads are longer, being now about 

 as long as the pronotum (Fig. 12). Up to this point the development 

 of the wings has been very gradual, the most pronounced change be- 

 ing the reversal of these organs between the third and fourth stages. 

 With the moult, which occurs at the end of the fifth stage, the insect 

 assumes the adult form (Fig. 13). The wings have now become 

 greatly elongated ; they are again reversed, so that the}- assume the 

 primitive position, with the second pair folded beneath the first. 

 This completes the changes through which these organs pass. 



So far as my observations go, there is but a single generation of 

 each species of locust during a year. In the majority of cases at 



See First Report of the U. S. Ent. Com., Plates I., II., and III. 



