SYNTOMIDAE MIMICRY 389 



[Europe] one is prepared by knowledge gained from bool;;s for 

 the appearance Sesia presents. Had one no knowledge of this 

 sort as to Sesiidae he would actually in the field [in Brazil] over- 

 look dozens of these little creatures without being aware of his 

 deception. The surprise at finding a quite different being in the 

 net from what one believes he has caught occurs daily in Brazil, 

 so rich in Lepidoptera." ^ The same intelligent observer says ^ 

 that a species of Macrocneme was observed by him to be exactly 

 like one of the blue wasps of the genus Fepsis. 



One remarkable point in these Hymenopteroid Syntomids 

 is their complete dissimilarity from their immediate allies. 

 They resemble very different Hymenoptera ; and not only 

 stinging Hymenoptera ; the Sessiliventres have a large share 

 of their attentions ; the numerous species of Bydaclia partaking 

 the appearance of the South American Sawflies in a wonderful 

 manner. Bees, Wasps of the most different kinds, and a variety 

 of Sawflies are beautifully paralleled, if one may use such an 

 expression, by these Syntomids. That shown in Fig. 194 has the 

 abdomen formed like that of a Petiolate Hymenopteron ; the 

 base of this part, moreover, resembles in a remarkable manner 

 the " median segment " of that Order. The constriction is, how- 

 ever, placed not at the base of the abdomen but beyond the second 

 segment. Thus the structure is not morphologically similar to 

 that of the Hymenoptera, for the median segment of Aculeate 

 Hymenoptera consists of only one abdominal segment, while in 

 this moth the corresponding part is formed of two segments. 

 Though anatomically inexact, the resemblance is, as to propor- 

 tions, correct ; and those who delight in the use of the imagination 

 will see that had the moth used only one segment for the imita- 

 tion, the result would have been less successful owing to insufficient 

 size. In his very interesting account of some Brazilian Syn- 

 tomids,^ Seitz describes a species of Trichura provided with a 

 long appendage that is held straight backwards during life ; and 

 he informs .us that this creature resembles a female Ichneumon, 

 the long process looking like the elongate ovipositor of the 

 Hymenopteron. Possibly the species from Demerara we figure 

 may resemble an Ichneumon we are not acquainted with, though 

 its colour and form rather suggest a likeness to an Aculeate. 



-'00^ 



' Ent. Zeit. Stettin, Ivi. 1895, p. 233. '^ Op. cit. li. 1890, p. 261. 



^ Snt. Zeit. Stettin, li., 1890, p. 263. 



