M YRMELEONIDES 457 



leon formicarium by Hagen and others ; M'Lachlan renamed it 

 M. europaeus, but now considers it to be the M. nostras of 

 Foiircroy. The popular name appears to be due to the fact that 

 ants -Formica in Latin, Fourmi in French form a large part of 

 the victims ; while lion the other part of the name is doubt- 

 less due to its prowess as a destroyer of animal life, though, as 

 Eeaumur long ago remarked, it is a mistake to apply the term 

 lion to an Insect that captures its prey by strategy and by 

 snares rather than by rapidity and strength. The imago of 

 Myrmeleon is of shy disposition, and is rarely seen even in 

 localities where the larva is abundant. It is of nocturnal habits, 

 and is considered by Dufour to be carnivorous. 



Considerable difference of opinion has existed as to the structure 

 of the mouth and of the alimentary canal in these larvae. Eeaumur 

 was of opinion that there exists no posterior orifice to the alimentary 

 canal, but Dufour ridiculed this idea, and stated positively that 

 such an orifice undoubtedly exists. It is also usually said that 

 the mouth is closed by a membrane. Meinert has recently exam- 

 ined these points,^ and he states that the mouth is not closed by 

 any membrane, but is merely compressed. He finds that there is 

 no posterior exit from the stomach ; that there is a compact mass 

 without any cavity between the stomach and the point where the 

 Malpighian tubes connect with the small intestine. The portions 

 of aliment that are not assimilated by the larva collect in the 

 stomach and are expelled as a mass, but only after the Insect has 

 become an imago. This peculiar excrementitious mass consists 

 externally of uric acid, and from its form and appearance has been 

 mistaken for an egg by several naturalists. The posterior portions 

 of the alimentary canal are, according to Meinert, of a remark- 

 able nature. The small intestine is elongate, slender, and is 

 coiled. There are eight very long and slender Malpighian tubes ; 

 a pair of these have free extremities, but the other six in the 

 posterior part of their course are surrounded by a common mem- 

 brane, and, following the course of the intestine, form ultimately 

 a dilated body seated on a coecum. These six Malpighian tubes 

 are considered to be partially, if not entirely, organs for the secre- 

 tion of silk for forming the cocoon, the coecum being a reservoir. 

 The canal terminates as a slender tube, which acts as a spinneret 

 and is surrounded by a sheath. A Complex set of muscles com- 

 1 Ov, DansTce Selsk. 1889, p. 43. 



