CADDIS-FLIES. 79 



PHILANISCUS PLEBEJUS. 



Philaniscus plebejus, Walker, Cat. Neuroptera Brit. 

 Mus., p. 116 (1852). Anomalostoma alloneura, Brauer, 

 Reise der "Novara," Neuroptera, p. 16, pi. 1, fig. 6 



(1865). 



(Plate IX., fig. 10, 7 larva removed from case, 9 larva 

 in its case, 8 pupa ; all magnified.) 



Although this little caddis-fly is neither interesting 

 nor attractive in its final condition, the strictly marine 

 hahits of its larva render it unique amongst caddis-flies, 

 and most remarkable amongst insects generally. To 

 Captain Hutton, of Christchurch, belongs the credit of 

 first discovering the transformations of this species, and 

 subsequent observations have in every way verified his 

 original statements, regarding the exclusively marine 

 habits of the larva. 



This insect is probably generally distributed along the 

 sea-coast throughout the whole of New Zealand, but at 

 present actual specimens have only been taken at Auck- 

 land, Wellington, and Lyttelton. 



The expansion of the wings is slightly more than ^ inch. The general 

 colour of the body is " dull-red with the sides of the thorax greyish. The 

 antennas are thick, pale tawny, ringed with grey, the apices dark grey; the 

 clypeus is clothed with golden hairs ; the head has four narrow lines of red 

 hairs. The legs are dull red. The anterior wings are grey, subhyaline, 

 tessellated with pale chestnut, with a thin, yellow, woolly coating. The 

 posterior wings are hyaline, the veins reddish, the dorsal margin near the 

 base clothed with black hairs. The inferior appendages in the male are 

 large, curved upwards, with the apices bent downwards ; in the female they 

 are acute" (Brauer). 



The larva inhabits rock-pools on the sea-beach, and is 

 commonest near low- water mark, where it is completely 

 outside the influence of any fresh water. It constructs a 

 cylindrical case of coralline seaweed, a few minute stones, 

 &c, being occasionally incorporated with the weed in the 

 walls of the case. The length of a case belonging to a 

 full-grown larva is generally about ^ inch. In 

 addition to the small fragments of seaweed, which form 

 the body of the case and are mostly arranged transversely 

 on its surface, long branching fragments are also fre- 

 quently attached. These accessories undoubtedly very 

 much increase the protective value of the case, and render 

 its discovery, amongst large clumps of seaweed, a task of 



