528 Scientific Proceedings, Royal Dublin Society. 



formed lasts from twenty-three to twenty-eight days. An elongated and 

 fully fed larva becomes transformed rapidly to the shortened quiescent 

 condition ; and usually on the second day after the cocoon has been com- 

 pleted the short and stout form is assumed. This condition persists for five 

 or six days, during which the larva remains in a passive condition and 

 exhibits little movement. 



When the development of the pupal structures is complete, the larval 

 cuticle splits open along the median line of tlie thorax, and along the epi- 

 cranial and frontal sutures of the head, and the pupa emerges in the cocoon. 

 The old cuticle is thrown off backwards, and is rarely seen attached to the 

 pupa. 



It is interesting to note here that the larvae of all the other species of 

 Longitarsus studied, so far as the writer is aware, possess similar feeding 

 habits by living in and feeding on the roots and stems of the adult's host 

 plant. Thus the larvae of L. echii Koch, feed beneath the root-bark of 

 Echium vulgare (53) ; Longitarsiis niger Koch, larvae also penetrate and feed 

 upon the roots of this plant. The larvae of Longitarsus tahidus F. live in 

 the root-tissues of Verbascum spp. (54) ; while the larvae of Longitarsus 

 luridus Scop, live in the stems of Ehinanthus sp. near the ground-level (55). 



(A) Duration and Characteristics of the Pupa. — The pupa remains quies- 

 cent in the cocoon, but is capable, if disturbed, of making considerable 

 movement by lashing the hinder region in circular motion. This movement 

 occurs as the pupa lies on its back, and is permitted by the articulation of the 

 abdomen with the thorax. When movement in the head region is desired, 

 the anal forceps are pressed firmly against the wall of the cocoon, and when 

 a hold is secured, the head is moved as desired. Thus the anal hooks serve 

 to anchor the pupa in the cocoon, and they also aid considerably in the 

 casting of the pupal cuticle. Pupae formed during the period extending 

 from the 1st till the 25th July were kept in soil, and the adults emerged 

 from the 14th July until the 8th August. The pupal stage therefore extends 

 from ten to fifteen days, with an average duration of twelve days. The pupal 

 cocoons are formed from 1| to 2| inches below the surface of the soil. 



Colour-changes in the Pupa. — When first formed the pupa is creamy white 

 throughout, and shows no trace of pigment in the eyes. After three or four 

 days pigment appears, and the eyes of the imago are seen as brown patches, 

 while the rest of the pupa is still white. As development proceeds, the 

 colour changes in many parts, so that just before the emergence of the adult 

 the pupa has become dirty white, while the eyes appear as dark-brown to 

 black areas occupying a considerable portion of the head region ; the tips of 

 the mandibles are orange-yellow; the femora pale-yellow, with a deeper 



