ZEUGOPHORA SCUTELLARIS 249 



MOULTING AND DEVELOPMENT OF PIGMENT 



Incidentally some observations were made on moulting and 

 the development of pigment. On April 15 the contents of one 

 box were examined. A half dozen larvae, the same number 

 of pupae, and two beetles were found. These two beetles were 

 just emerging from the pupa case. They had freed all parts 

 except the tarsi and a portion of each antenna. They were 

 pulling and hauling energetically to free the feet. The remains 

 of the pupa cases were crumpled into a shapeless film entangling 

 the feet. 



At this time the black pigment had not yet appeared. The 

 beetles were almost uniformly straw-color except the elytra 

 and antennae which were slightly brownish. On being placed 

 in a lighted room they attained the black pigment within twenty 

 four hours. It may be that light and oxygen are factors in the 

 production of pigment, but pupae exposed to light do not de- 

 velop pigment. All beetles were quite dark when they emerged 

 from the soil, although the black became more intense later. 

 They seem to remain in the ground a day or so after moulting 

 the pupa skin, possibly longer. 



DETAILED DESCRIPTION OF LARVA, PUPA AND IMAGO 



* 



Kaltenbach in his Pflanzenfeinde (74, p. 544) gives a good 

 brief description of the larva of Z. fiavicollis. He states also 

 that the metamorphosis takes place in the earth and that the 

 summer brood appears in May of the following year. He gives 

 no figure of the larva and his is the only reference in biological 

 literature to the early stages of the Zeugophora. Up to the 

 present time there has been no published description of the pupa 

 of any member of this genus. Kaltenbach says of Z. scutellaris 

 "Wurde von Apotheker Hornung und Dr. Suffrain auf Populus 

 nigra gefunden. Ersten Stande unbekennt." 



