8 Imms, Homoptcrous Insect Phroinnia {Plata) viarginella. 



small rounded nuclei. The wax-secreting cells are 

 specialised cells derived from the hyperdermis and are 

 greatly elongated with the nuclei at their inner ends. 

 Each wax cell is traversed by an elongated cavity into 

 which the wax secretion congregates, to be ultimately dis- 

 charged through the corresponding pore to the exterior. 

 With regard to the structure of the cuticle, Bugnion 

 and Popoff remark : " L'emploi d'un grossissement plus 

 fort a permis de constater que les stries verticales ne 

 sont pas des canalicules, mais repondent au contraire 

 aux lammelles chitineuses qui limitent les pores. Les 

 pores sont les espaces clairs compris entre les stries. 

 On voit de plus : ( i ) que chaque pore surmonte une cellule 

 unique : (2) que le pore offre a sa base un collet retreci, 

 large de 2| /x, la chitine I'enserrant a ce niveau dans un 

 epaississment en forme d'anneau. La partie profonde de 

 la cuticle apparait sur les coupes obliques comme une 

 lame jaune percee de trous ronds a contours tres accuses. 

 Ces trous repondent aux collets des pores." There has 

 been a good deal of difference of opinion as to the 

 chemical nature of the waxy filaments of the larvae of 

 the Flatid group of the Fulgoridae. Spinola^" makes a 

 general statement with regard to the wax secreted by the 

 ' Fulgorelles." He says that it dissolves entirely in 

 alcohol and gives off a distinct odour of horn when burnt 

 in a flame of a candle. Cotes" states that Murchison 

 examined the white filaments of a Fulgorid which was 

 either P. inarginella, or a species closely related to it, and 

 remarked that they were composed of what he believed 

 to be wax. An examination made by T. H. (now Sir 

 Thomas) Holland on Coates' behalf of the filaments of 

 larva; of P. niarginella, preserved in the collections of the 



i« "Essai sur les Fulgorelles." An. Soc. Ent. Fr., T. viii,, 1839, 

 p. 197. 



*i Loc, cit., p. 92. 



