18G1.] 4S 



and number of joints of the antennjo), which are important for classification 



Another division, introduced by Hartig is based upon the habits of the 

 insect only, without a corresponding structural character to distinguish them. 



Almost all the insects of Section I (with a narrow radial area and basal 

 areolet) and some of Section II, (with a short, broad radial area and inter- 

 mediate areolet) are called by him true gall-Jliea CFsenidcs), they being 

 the originators of the galls A part of the Cynipidtc of Section II, and a 

 few of Section I, are mierdy parasites in the galls produced by the gall- 

 flies of the first division. Ilartig calls them Inqidlinse,. A third division 

 (called the parasites by Hartig) is formed of the rest of Section II and 

 the whole group of Ficjitidae.. " The habits of this division, says Hartig, 

 are little known ; some, as Xjjstus Ilartig (^Allotria Westw.) live parasiti- 

 cally in Aphides; others in larvae of diptei'a." 



That these differences exist in nature is certain; but a great deal remain?* 

 to be done yet before attempting a natural distribution of the known gen- 

 era and species on this basis. It seems hardly probable for instance that 

 species of the same genus (as stated by Hartig about Neurvterus), should 

 sometimes be true gall-producers, sometimes parasites. 



It will be seen below that I have reared from galls several species, the 

 characters of which are those of Figitidee and which ought therefore to 

 belono; to the first or second and not to the third of Hartif-'s divisions, 

 where the Figitidse are placed. Again about the true relation of the Jn- 

 quiUnse to the Fseiiides, their food, the mode of introducing their eggs in- 

 to foreign galls etc., nothing is known and 7wt a single direct observation 

 seems to be extant. The fact of their parasitism is thei'efore merely infer- 

 red from the circumstance of their having been reared from the same galls. 



Another unsettled and greatly vexed question with reference to gall-flies 

 is that of their sexes. According to Hartig, all gall-flies of the second 

 and third division (Inquilinpe and Farasites) and some of the Fseni<les, 

 (the gen^era Trigonasjns^ Spathegaster^ Teras and Andricus) occur in both 

 .sexes. The remainder of the Fsenides (the genera Ci/nips and ApophijJ- 

 lus Hartig, Syn. Biorhiza Westw.) are known in the female sex only. 



Neuroterus has again an intermediate position; those species of this gen- 

 us which are gall-producers, were known to Hartig in the female sex only, 

 whereas he possessed a male of one of the species belonging to the luqifil- 

 inse.. 



Hartig says that he examined at least 15,000 specimens of the genus 

 Cynips, as limited by him, without ever discovering a male. To the same 

 purpose he collected about 28,000 galls of Cynips divisa and reared 9 to 

 10 thousand Cynijjs from them; all were females. Of ('. folii likewise 

 he had thousands of specimens of the female sex without a single male. 



