416 SYNOPTIC COLLECTION. 



number and function as in all the most generalized 

 groups, but the running type of insect has changed into 

 the leaping type, and this is true not only of the adult 

 but also of the young larva. 



With the development of wings the pupa (No. 1019, 

 PI. 1018, fig. 2) takes on some of the features of the 

 adult. The first thoracic segment becomes differentiated, 

 serving to protect the parts, and the two hinder segments 

 become consolidated until in the adult (No. io2o,Me?an- 

 oplus femoratus Scudd., $ ; No. 1021, ?; PI. 1022, fig. 

 i, side view of $\ fig- 2, dorsal, with view of dissection of 

 9 ), they are so complex in structure that it is difficult to 

 make out their boundaries with absolute certainty. 



The abdomen (PI. 1022, figs, i, 2) retains essentially 

 its primitive simplicity, though a fold has appeared on 

 either side above which, near the anterior edge of the 

 segment are situated eight pairs of spiracles, while there 

 is a pair in each of the posterior segments of the thorax 



(fig- 3). 



The Acridiidae have a tracheal system consisting not 

 only of air tubes but also of a large number of air sacs 

 (fig. 3). When the tubes and sacs are filled with air, the 

 body is greatly lightened and the insect is able to fly con- 

 siderable distances. The second pair of wings (fig. 2) are 

 most useful in flight. When at rest these organs are 

 folded lengthwise like a fan and lie straight with the 

 body ; hence the name of Orthoptera or straight-winged 

 insects. The hind wings are often large and handsomely 

 colored, as in one of our largest Locusts, Dissosteira 

 Carolina Linn. (No. 1023, $ ; No. 1024, 9 , with wings 

 spread). 



The ovipositor (PL 1022, figs. 2, 3) of the female con- 

 sists of horny spike-like organs situated at the end of 

 the abdomen and well fitted for digging holes in the earth 

 in which to place her eggs. 



Most of the parts of the locust exist on a large scale in 

 Dictyophorus reticulatus (No. 1025), and for this reason 



