22 REPORT OF NEW JERSEY STATE MUSEUM. 



It will be noted that all the orders of the first series are terres- 

 trial in all stages, and that in none of them are the wings folded 

 in any way. 



The second series of the mandibulates is that in which the 

 first segment of the thorax became separated from and movable 

 upon the second, while the second and third became closely 

 united. In all cases the head is set into the first thoracic segment, 

 and there is never any distinct neck between. This series 

 branched early into two main divisions, one of them adapted to 

 living on land, the other living in or under water. 



The Plecoptera, or plaited winged forms known as stone-flies, 

 have the wings net-veined, and the hind wings are folded or 

 plaited beneath the fore wings when they are at rest. The 

 larvae live under stones in water, breathing by means of gill- 

 tufts ; the pupae are active and the metamorphosis is thus incom- 

 plete. 



An advance is noted in the Platyptcra, where the transforma- 

 tions become complete. In general appearance they are not 

 unlike the stone-flies, but are more compactly built, with the 

 wings folded in much the same way. They are known as fish- 

 flies, and some of them are very large and formidable in appear- 

 ance. The larvae live on the bottom of streams under stones, 

 breathing through gill-tufts and usually coming to the shore to 

 pupate. The largest of these larvae are known to fishermen as 

 Heligramites, and are often gathered in numbers as bait for 

 bass. 



In the terrestrial series the roaches first became developed, and 

 from them the other members of the order Orthoptera or 

 straight-winged insects, grasshoppers, katydids, crickets and the 

 like. In all these the fore wings are actually or comparatively 

 narrow, more or less thickened in texture, while the hind wings 

 are folded fan-like beneath them. The pupal stage is active, and 

 the transformation, therefore, incomplete. Some of the roaches 

 had, and some yet have, the secondaries transversely folded, and 

 from this type we derive the Dermoptera and Coleoptera. 



The Dermoptera, or ear-wigs, resemble small, short-winged 

 beetles, with a curious, forceps-like anal appendage, which they 



