The Zoologist— July, 1869. 1731 



forward to double the usual term of life in order to be able to elucidate 

 this question. 



Zaddach has most carefully noted the literature of the species of 

 Cimbex, and instituted a comparison between the various authors. 

 He arrives at a theory regarding the so-called variabilis which, read 

 by the light of what he and his friend Brischke have been able to 

 make out from their attempts at rearing this species, gives the follow- 

 ing result. The Cimbex variabilis ofKlug, in all probability, em- 

 braces four species, the imagos of which bear a strong resemblance 

 to each other — 1, the subject of the present description, Cimbex 

 connata, Schrank, called by Ratzeburg C. Humboldtii, and whose 

 very distinct larva is always found on the alder; 2, Cimbex Betulae, 

 Zadd., the female of which is known as C. sylvarum, F., and whose 

 larvae (at all events in Germany) live exclusively on the birch ; 

 3, Cimbex Fagi., Zadd., a hitherto doubtful species, — according to 

 Drewsen and Dahlbom the larva feeds on the beech, and is distin- 

 guished by the dark brown tint of the skin ; lastly, 4, Cimbex Saliceti, 

 Zadd., the pale coloured larvae of which are found feeding upon two 

 species of willow. These larvae are described and figured by Bonnet, 

 Lyonet and De Geer : I have also in my possession an unpublished 

 description, (with a beautiful drawing), by C. B. Voet, treating of the 

 last-named species. 



Whether these species are constant can be ascertained only by ex- 

 periments conducted with great care, and requiring much time to be 

 devoted to them. It seems to me that our country is not particularly 

 well adapted for the investigation, as being poor in individuals of the 

 genus Cimbex, and that we may rather look for light from the East — 

 for example, Poramorania. 



We will now return to the special consideration of our subject. 



I think I may hazard the opinion that the female lays her egg in 

 the petiole of the leaf of the alder, added to which I should be dis- 

 posed to consider it highly probable that she deposits but few eggs, 

 and that these are placed at considerable distances apart. De Geer 

 states that on opening the abdomen of a female he found it to contain 

 rather large eggs of an oval shape and pale green tint ; it is not 

 certain, however, that he actually examined a female of Cimbex 

 connata. 



Although the imagos appear in May, I have not succeeded in find- 

 ing a larva before the month of September. The youngest larva 

 which 1 have observed was found on the 1st of September, 1861 ; 



