INSECTA. 299 



ERICHSON, Jahresbericht, Arch.f. Naturgesch. 1843, 8. 270), it is pos- 

 sible that sometimes young specimens of Podura may be placed 

 under the genus Lipura (Anurophorus NICOLET) ; but this entire 

 genus is not on that account to be rejected, for it is very usual that a 

 young form in a natural family should be represented by a per- 

 manent generic form. The most remarkable deviation in this family 

 is that of the genus Anura GERVAIS (Achorutes NICOLET), where in 

 place of jaws there is a suctorial mouth ; see NICOLET op. cit. p. 33, 

 PL iv. fig. 5. 



Sminthurus LATR. Thorax and abdomen conjoined into a 

 globose body. Antennas geniculate; terminal portion of antenna 

 setaceous, multi-articulate. 



GUERIN, Iconogr. Ins. PL 2, fig. 4. (Add sub-gen. Dicyrtoma BOURLET). 



Podura LATR. Thorax separate from abdomen ; body elongate, 

 with abdomen narrow, oblong. 



A. Mandibles and maxillae none. Suctorial tube conical. 



Anura GERV. (Achorutes NICOLET not TEMPL.) No forked tail. 

 Abdomen rotundate behind. 



B. Mandibles and maxillae. 



a) Antennae short, with four or five joints. 



Lipura BURM. (Anurophorus NICOLET). Body not scaly. Abdo- 

 men, instead of a forked tail, terminated by two very small conical 

 diverging tubercles. 



Sp. Podura fimetaria L., Lipura ambulans GERV. (nat. Pod. ambulans L.), 

 DE GEER, vii. p. 33. PI. 3, figs. 5, 6. NICOLET op. cit. PI. 5, fig. 2, com- 

 mon in garden-mould and in flower-beds, ivory-white, I line long. 



Achorutes TEMPLETON, Hypogastrurus BOURLET, Podura NICOLET. 

 Body not squamose. Tail forked, short. 



Sp. Podura aquatica L., DE GEER, Ins. vn. PL n. figs. 1113, NICOLET 

 op. cit. PL 5, fig. 4 ; one line long, very common with us, forms large 

 black spots on the water, near which other white spots are floating, formed 

 by the cast skins. 



6) Antennae longer than head. 



Genera Isotoma BOURLET (Degeeria NICOLET, Desoria NIC.), 

 Heterotoma BOURLET, Orchesella TEMPLETON, Lepidocyrtus BOURLET 



