106 Mr. J. O. VVestv.'ood's Description of some Insects 



table to these insects, and not to any animal principle in tlie body 

 of the sponge itself. 



These insects, which he has placed in my hands for examination 

 and description, are as anomalous as the substance they inhabit. 

 They are of a small size, not exceeding one-seventh of an inch in 

 length, of a soft membranous consistence, and of a pale greenish 

 colour, which is more vivid in the legs. They are depressed, and 

 of an oblong-oval shape, (fig. 1 upper, 2 underside, magnified,) 

 and composed of thirteen joints, the first of which, forming the 

 head, is small, having a black patch on each of the posterior angles, 

 wherein are several large granular shining ocelli (fig. 3 under, 4 

 lateral view of the head). The antennae (fig. 5) are nearly half 

 the length of the body, arising from a thickened basal joint in front 

 of the eyelets ; the terminal part of the antenna is exceedingly 

 slender, cylindrical, and very indistinctly articulated. The upper 

 side of the head is furnished with several long setae ; its underside 

 is very convex ; the lower lip being of moderate size, and termi- 

 nating in a transverse line, behind which are two short oblique 

 darker spots ; the sides of this lip are greatly widened towards the 

 base. On each side of the sides of this lip another line extends in 

 an oblique direction to the lateral anterior angles of the lip, and 

 from this spot on each side arise two long and exceedingly delicate 

 setse, as long as the antennce, and constantly porrected, having a 

 small space between them at the base, where they are directed up- 

 wards. One in each side of these two pairs of setae is darker- 

 coloured and stronger than the other. They are entirely destitute 

 of articulation. Such is the entire structure of the mouth, as far 

 as I am able to perceive it ; thus there are no rudiments of labrum 

 nor palpi ; the mandibles and maxilla are represented by the four 

 porrected set£e, and the lower lip is destitute of ligula and palpi*. 



The thorax is composed of three segments, of which the pro- 

 thorax is the smallest. To each of these three segments a pair 

 of rather long, slender legs (fig. 8) is attached, composed of a 

 strong coxa, short trochanter, robust femur, elongated tibia, and a 

 two-jointed tarsus, destitute of any terminal unguis ; the legs are 

 sparingly furnished with long, slender, rigid hairs. The upper 

 surface of these segments indicate not the slighest appearance of 

 wings, or their rudiments. The nine terminal segments of the 

 body constitute the abdomen ; the first of these is smaller than 

 the metathorax, and the remainder become gradually smaller ; they 

 are furnished at each side with a small setigerous tubercle, which 

 is larger in the terminal segments (fig. 9), and yi which the setae, 



* We might, perhaps, consider two of these seta; to be the labial lobes, and 

 two to represent the maxillae, the mandibles being obsolete. 



