69 



aterrimus) or in canals, ditches, marshes and puddles in spring 

 (Limno ph ilu s centralis, L.vittatus). 



In flowing water, in brooks and streams, the conical sand cases are 

 short, wider anteriorly, dor sovent rally compressed and streamlined 

 (Figure 102) with a flat ventral surface (Leptocerus annulicornis, 

 L. excisus); the anterior opening of these cases is displaced ventrad 

 and is pressed to the stone to which the larva clings with its forelegs. 



FIGURES 101 and 102. Cases built of mineral particles: 



101 — smooth cases of limnophilic species covered with fine sand grains (after Hickin): 

 Mystacides longicornis (A), Limnophilus centralis (B); 102 — smooth 

 cases of rheophilic species: Leptocerus annulicornis (A), L. excisus (B), 

 Thremma ga llicu m (C — after Ulmer). 



(70) 



FIGURES 103-105. Cases covered with sand: 



103 — cases covered with fine sand and detritus: Mystacides azurea (A), Anabo- 

 lia soror(B); 104 — cases covered with coarse sand of rheophilic species: Potamo- 

 phylax stellatus (A), Dicosmoecus palatus (B); 105 - case of Mola nna 

 a n g u s t a t a with wings. 



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