AET. 25 MEGARIDINAE AND CANOPINAE McATEE AND MALLOCH 6 



the imagines of which are rather depressed) are relatively flattened. 

 The nymphs of all have 2-segmented tarsi. 



The coptosomatine nymphs agree with those of Pentatominae ii> 

 having all of the sutures between segments of the dorsum of the abdo- 

 men well marked, and in having three about equally separated pairs 

 of dorsal ostioles. They are thus more closely linked with the Penta- 

 tominae in the nymphal than in the adult state, and all things con- 

 sidered must yield the palm for specialization to Canopinae and 

 Megaridinae which are as strongly distinguished in the immature, as 

 in the adult stages. The nymphs of these latter two subfamilies are 

 as much as, or even more, inflated than the adults, and are heavily 

 chitinized and highly polished dorsally. 



In nymphs of Canopinae there are three pairs of ostioles, the ante- 

 rior pair being about twice as far apart as the other two pairs (fig. 

 25), and the sutures of the abdomen basad of those bearing the osti- 

 olar openings are extremely difficult to distinguish. A striking 

 character of these nymphs is the distinct central division of the basal 

 two exposed sternites. We figure (figs. 24-25) both the ventral and 

 dorsal aspects to show the anatomical features. 



In nymphs of Megaridinae the segmentation of the dorsum of the 

 abdomen is still more obscured, being visible with any distinctness 

 only on a small definitely marked-off section of extreme apex oi- 

 abdomen. Material is too scanty to permit of clearing a specimen 

 to reveal ostiolar characters. The basal segments of the venter are 

 undivided. 



SYSTEMATIC TREATMENT 



KEY TO IMAGINES OF THE THEBB SUBFAMILIES 



1. Thinning of fore wing extending from radial side, the costa produced far 

 beyond base of membrane, there thicl^ened and broadened (though tlie 

 apex is acute), and serving as a support to the numerous longitudinal 

 veins, most of which are directed obliquely across membrane from costal 

 to radial side, and the bases of which are connected by a long curved vein 

 (fig. 18) ; almost the entire sternal surface opaque; anterior and interior 

 margins of propleura not elevated; first sternite in some cases broadlj? 

 exposed laterally and evanescent medianly, in others entirely concealed; 

 sutures between abdominal segments in some cases traceable, in others 

 not, to margins of venter ; antenna obviously 5-segmented, short segment 

 between first and third antennal segments easily distinguishable; tarsi 



with 2 segments; sensory hairs longitudinally arranged Coptosomatinae. 



Thinning of fore wing extending fi'om costal side (figs. 6, 20), the costa not 

 produced, truncate apically, the fewer veins of membrane, the bases of 

 which are not connected bj'^ a curved vein, arising from the radial region 

 of corium and curving toward costal margin ; notable portions, or all, of 

 sternal surface not opaque; anterior and interior margins of propleura 

 elevated, forming a deep sulcus (fig. 2) ; antenna 5-segmented, the short 

 segment between first and third segments more difficult to see than in 

 Coptosomatinae, it being necessary to clear the antenna in some cases 

 to reveal it 2 



