23 



striking peculiarities. The pronotum varies in length, but its 

 hind angles always attain the tegulae; the usual divisions remain 

 distinct, with well defined sutures. The thorax of the males 

 throughout the whole family in general resembles that of these 

 females. That the males should remain in this comparatively 

 primitive condition may*at first sight seem anomalous, but it is 

 not really so, when one considers that the great modification ot 

 parts in the females of the highly evoluted forms is obviously 

 entirely in connection with the habit of seizing and holding their 

 prey, and not in any way due to sexual causes, such as would 

 iijfluence the other sex. 



Turning to one of the most specialized winged forms, such 

 as N'codryiiius, we observe profound modifications of the tho.ax 

 and of the front legs, the latter being lengthened in all their 

 parts in a highly abnormal manner. The pronotum is remark- 

 ably elongate and further extension forwards (even to an increase 

 Ci one-third the total length) is given by the development and 

 dorsal position of other of the prothoracic elements. The prono- 

 tum itself is much narrowed behind and unusually mobile, but in 

 spite of its great length the posterolateral angles fail to reach, 

 and are often very remote from the tegulae. 



In the apterous forms such as Pscudogonatopus the thoracic 

 sclerites attain the greatest modification of all. Here the meso- 

 notum is reduced to a small narrow bridge betw^een the prono- 

 tum and propodeum. Ashmead (Mon. Proct. p. 82) evidently 

 mistook the pronotum of Goiiatopiis for the mesonotum, when 

 he says "the latter" (i. e. mesothorax) "elongate and humped 

 at the middle and separated from the metathorax by a strong- 

 constriction." This strong constriction is the mesonotum itself; 

 and the great sclerite in front of it (often separated by an im- 

 pression into two lobes) as is easily seen by comparing it with 

 Neodryinns and other winged genera, is the mobile pronotum. 

 The small, narrow, true mesonotum is usually without division, 

 but in some forms of these apterous insects there is a very dis- 

 tinct posterior or scutellar division; and in some cases the meso- 

 notum and its scutellum can easily be removed entire from the 

 pronotum and propodeum. In some of these apterous forms, 

 the lateral and sternal elements of the mesonotum become en- 

 tirely fused with the propodeum, and no sutures at all remain 

 bv which the divisions may be distinguished. 



(c). The raptorial front legs. 



If we exclude a few genera of comparatively unspecialized, or 



