210 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 37 



Of course, the larvae of Coleoptera with a speciahzed diet (miners 

 included) present less plasticity than Hymenoptera Tenthredinidae, 

 and more than Lepidoptera, but as a rule their modifications have a 

 similar tendency. 



III. LARVAE OF PARASITIC COLEOPTERA HYPERMETABOLA 

 (RHIPIPHORIDAE) 



The Rliipiphoridae are protelic parasitic Coleoptera for the most 

 part hypermetabolous and generally developing at the expense of 

 Hymenoptera and Blattoidea (the Pelecotomini are thought to live at 

 the expense of xylophagous larvae and to be euholometabolous). 

 The hypermetabolous forms exhibit an asynchronous larval dimor- 

 phism, viz, two very different larval phases following each other in 

 order of time and strictly related to the "necessities" (let us call them 

 so for the sake of clarity) and complications of their life cycle. 



In order to discuss them, we shall refer to the Rhipiphorini (making 

 use of what I learned in 1936 regarding Macrosiagon ferrugincum 

 flabellatum F., fully confirmed in 1952 by the North American biolo- 

 gists Linsley, MacSwain, and Smith on Rhipiphorus smithi Linsl. and 

 MacSw.) and Rhipidiini (making use of the recent work of CI. Besu- 

 chet (1956) on Rhipidiiis quadriceps Ab.). 



Macrosiagon ferrugineum develops at the expense of a large soli- 

 tary vespid eumenid, Rhynchiitm ocnlatiim Spin., which builds its nest 

 in the reeds of Arundo donax and massively nourishes its offspring 

 with the entire caterpillars previously paralyzed. 



The coleopteran female (dwarf in respect to Rhynchium, a thin, 

 weaponless insect) to enable her larvae to reach the host shelter 

 chooses an indirect way and lays a large number of eggs on the plants 

 on which the hymenopteran usually lives and feeds. After hatching, 

 the larvae (of the first phase) take care of attaching themselves to the 

 foraging Rhynchium individuals, and some of them succeed in having 

 themselves carried to the nest of the destined victim. Having reached 

 this place, the larva waits until the host larva comes up to feed, then 

 penetrates inside the host, stays for some time in the superficial sinus 

 of its body cavity, and finally sinks. 



During the endozoic life, the larva feeds on the victim's humors, 

 swelling enormously ; afterward it makes its way through the host 

 integument, moults, sheds the old covering to plug in some way the 

 wound in order to prevent a too severe hemorrhage and, transformed 

 into a larva of the second phase which will live as an ectophagan, 

 comes out. 



