Séance du I7 Novembre 1920 91 



periphery, bursts open Hic iiymphal onvelopo, expands 

 Ihe eyes then, penetraling Ihe wjni^s, caMses thein lo 

 unfohl. (After Hkxnix.iy, H)l).i, p..'):}!). 



In Ihe ease of llie F^epidoplera, Ihe aelion ol' hlood 

 pressure in Ihe spreading ol liie wings was aheady 

 pointed oui i)y Swammkhuam (1(5()8), Ri:ArMrii (1737,1, 

 2nd Pari, p. '■\ô\) and, among modern iiivestigalors, by 

 I'ANCiiiTius (1884) and Gonix (1894). 



It is thus seen that these lacls are generally true. 

 The manner of spreading the wings observed in Eìììfmsd 

 must without doubt i)e Ihe same in llie ease of Ihe 

 Liljelhilidae, the Lepidoplera, the (^ieadidae, in all 

 inscels whose wings, mueh folded and erumpled, 

 s|>rea(l in a short lime. 



Among Ihe Coleoplera, of whieh the elylra and 

 wings develoj) gradually, Ihe aelion of Ihe blood 



the cervieal sae, the function of wliicii during the hatching 

 ofAcridiid hirvae he has determined, also lakes part in the 

 moulting process. At each moult, the mcmhrane which 

 joins the head to the |)rolhorax on the dorsal side, is able to 

 swell by tilling with blood; it then exerts on the doi-sal 

 integuments a strong p ressuie which ruptures tliem. This 

 swelling of the eervieal sae is j)rodueed in the same manner 

 as the lengthening of the abdomen at the time of laying; the 

 animal fills its crop with air till it is stretched eomj)lelel\ : 

 nuiseular contractions, even very slight, are then sufficient 

 to drive the blood easily into the cervical sac. The pressure 

 exerted by the latter is greater in proportion to the amount 

 of air crammed into the crop. .\t the time of moulting, the 

 tracheae contain very litlle air, the sacs are llattened and 

 empty, thus the tracheal system takes no part in the moulting 

 process". As the lining of the tracheae is shed at each 

 moult, it is other wise obvious that Uiey cannot lake any 

 active part in the process. (Translator), 



