482 NEUROPTERA CHAP. 



Sericostomatides, like the Limnophilides, is a group rich in 

 species ; the larvae are chiefly found in streams. They form 



portable cases out of sand and stones 

 (Fig. 325, B, case of Crunoecia irrorata) 

 in preference to vegetable matter. It 

 is here that the genus Helicopsyche, 

 which for long was an enigma to 

 naturalists, is now placed. This genus 

 consists of Insects whose larvae form 



spiral cases, similar to small snail shells, 

 FIG. 327. Cases of Helicopsyche . 



shuttieworthi. (After von Sie- of sand or minute stones. These objects 



bold.) A, Natural size ; B, C, Qccur j n var i ous par t s o f the World. 

 magnified. * 



Fritz Miiller 1 has informed us that the 



larva inhabiting one of them, when it withdraws entirely within 

 its abode to repose, takes the precaution of anchoring its snail- 

 like habitation, fixing it to a rock or stone by spinning some 

 temporary silken threads. The respiratory filaments in this 

 group are filiform. 



Leptocerides. The first group of the division Aequipalpia ; 

 so that there are five -jointed maxillary palpi in both sexes ; 

 these organs are frequently developed in a remarkable manner. 

 The antennae are usually extremely long and slender. The case 

 of the larva is portable (Fig. 325, A, case of Odontocerum) ; 

 the respiratory filaments are not very conspicuous ; they form 

 short tufts placed on various parts of the abdomen. Miiller 1 has 

 called attention to a species whose larva lives in Brazil between 

 the leaves of Bromeliae on trees. 



The Oestropsides is a small group, and has recently been 

 reduced by M'Lachlan to the rank of an inferior division. 



Hydropsychides. An extensive group, in which the larvae 

 are believed to be chiefly of carnivorous habits. They vary, 

 according to species, as to the nature of the respiratory 

 filaments, and live in fixed abodes ; these are less tubular than is 

 the rule with the portable cases, and are formed from pieces of 

 sand and stone spun together and fixed to larger stones under 

 water. Sometimes several larvae live together in loosely compacted 

 structures of this kind, and only form true cases when about to 

 undergo their metamorphosis. Miiller describes 1 a Brazilian species 

 of RhyacopTiylax as forming a case in which the mouth-end has a 

 1 Zeitschr. iviss. Zool. xxxv. 1881, PI. IV. fig. 6. 



