THE CANADIAN ENTOMOLOGIST. 187 



pupating under the larval skin beneath stones, boards, etc., in 

 damp situations. He did not mention when they could be found. 

 Last summer (Aug. 6, 1913) while collecting along the bank of 

 Salmon River I was attracted by the large number of empty 

 larval skins of this species. Though I had noticed such skins prev- 

 iously I had always discovered them empty. In searching over a 

 large number I was fortunate to find two pupae not yet transform- 

 ed. Nearly a month previously the adults had been observed 

 egg-laying, so evidently the time of pupation extends over a 

 considerable period. How long the pupal period lasts I did not 

 determine. 



The pupae are found on the under side of stones, boards, etc., 

 in damp situations. I found the larval skins very abundant under 

 loose rocks overhanging the Salmon River. These sedimentary 

 rocks are soft and many cracks extend in all directions, retaining a 

 considerable amount of moisture. The last larval skin is firmly 

 attached to the rock. Under this skin the pupa is formed. The 

 larval skin on the ventral side splits transversely just in front of 

 the mouth parts and is forced back to the tip of the abdomen 

 where it remains (fig 4). The pupa is pure white in colour and 

 very tender. It is held in place under the larval skin by the un- 

 shed anterior ventral portion and the shed skin at the caudal end. 

 In this way the pupa is prevented from coming directly in contact 

 with the hard underlying rock, etc. 



Although there are several extended descriptions of the larva 

 and larval structures I have found scarcely a word regarding the 

 pupa. The pupa is pure white in colour, measuring 4.5-5mm. long. 

 The anterior end is firmly held in place by the remaining portion 

 of the larval skin, while the end of the abdomen remains beneath 

 the cast larval skin. However, if one carefully lifts the pupal head, 

 then loosens the abdomen he will be surprised to find the pupa 

 still firmly held in place. Carefully pushing the pupa it soon 

 breaks away and discloses a process on each side extending from 

 the latero-dorsal angles of the first abdominal segment. These 

 processes are firmly attached to the lateral walls of the envelop- 

 ing larval skin. A dorsal view of the pupa showing these peculiar 

 processes is shown in fig 5. The pupa is perfectly smooth without 

 any spines or setae. There are eight abdominal segments on the 



