408 SYNOPTIC COLLECTION. 



trary, they are adults which are differentiated in a peculiar 

 way for a particular sphere of action, thereby becoming 

 examples of specialization by the suppression of organs. 



An interesting modification in structure for the pur- 

 pose of defence is found in the soldier of the genus Eu- 

 termes (PL 993, figs. 1-6). Its head (fig. 5 ; fig. 6, x 25) 

 extends forward into a beak or "gun " and from this beak 

 the animal discharges glutinous pellets or shot l which 

 are so sticky that its enemy is quickly disabled. Eu- 

 termes is one of the smaller termites ; the figures of the 

 worker (fig. 4) and of the soldier are enlarged five diam- 

 eters, and the remaining three figures are natural size. 

 The winged female is seen in fig. i, and the wingless 

 queen, before the period of egg-bearing begins, in fig. 2, 

 while fig. 3 is the mature queen with her body distended 

 with eggs. 



The wings of the termites when extended are broad, 

 and hence the name of Platyptera (meaning broad wing). 

 When spread they give an unusually broad effect to the 

 insect. They are about equal in size and structure in the 

 termites and hence the name Isoptera which is often 

 given to this order. 



Oligotoma michaeli McLachlan (PL 994, fig. i, larva; 

 fig. 2, "starved" pupa; fig. 3, adult) of the family Em- 

 biidae, is interesting for the reason that it represents a 

 case among insects in which both pairs of wings are 

 developed, but which are so weak that they are practi- 

 cally useless. The thoracic segments to which these in- 

 efficient organs are attached are unconsolidated and the 

 insect is described as "feeble." It seems as though the 

 wings were ready to drop off and in time Oligotoma 

 would become wingless. 



The Psocidae are like the termites in many ways but 

 the arrangement of the veins of the- wings differs from 

 that of any biting insect (Comstock) and these organs 



1 Dudley, Trans. N. Y. Acad. Sci., VIII, 1889, p. 87. 



