12 CELLULES. 



and of the cubital four ; but sometimes at the apex 

 of the outer radial cellule there may be a small cellule 

 called the appendicular (Hi/lotoma), but it has never 

 any nervures. When two cells are present, their 

 relative length depends upon the place in which 

 the dividing nervure is received according as it is 

 received nearer the apex or the base of the cellule. 

 The cubital cells are never less than three with the 

 TenihredinidcB, but may be two only with Oryssus. 

 When there are three cubitals, either the first or 

 second may be the longest. The first is small with 

 Dolerus and Cryptocampus, large with Emphytus, 

 Cladius. If small, it never receives a recurrent ner- 

 vure, but in the other case it may receive one only or 

 two. If the first is small the second always receives 

 two nervures. When there are four the first is small 

 and never receives a nervure, but the second and third 

 receive one each, or the second may receive both, e.g. 

 Nematus. 



On the lower side of the wing, between the median 

 and anal cellules, and bounded by the anal nervure 

 above and the accessory beneath, there is an elongated 

 cellule called the lanceolate cellule, which is of great 

 value in classification ; and it is moreover peculiar to 

 the Tenthredinidce. According to the position of the 

 accessory in relation to the anal nervure, the cellule 

 assumes four different forms. 



I. The accessory nervure issues from the middle of 

 the cellule, where it curves down from it, to unite with 

 it again at the end, thus forming an elongated, sharply- 

 pointed cellule at the end. This is called a petiolated 

 lanceolate cellule, and it occurs with the following 

 genera : Nematus, Dineura, Schizocera, Fenusa, Blen- 

 nocampa (PL X, fig. 12 d). 



II. The accessory nervure unites with the anal not 

 far from its origin, then breaks off, but issues again 

 from the anal nervure towards the middle, when it 

 curves down to become united with it at the end. 

 There are thus two unequal cellules formed, a small 



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