454 INSKCTA. 



The second section of the Hymenopterp., that of the Aculeata, 

 differs from the first in the absence of the ovipositor. A concealed 

 and retractile sting composed of three pieces usually supplies the 

 place of it 'in the females, and in the neuters of species which form 

 communities. Sometimes, as in certain Ants, the sting is wanting, 

 and the Insect defends itself by the ejaculation of an acid liquid con- 

 tained in special glandular reservoirs. 



The Hymenoptera of this section always have their antennae sim- 

 ple, and composed of a constant number of joints, namely, of thirteen 

 in the males, and twelve in the females. The palpi are generally 

 filiform, those of the maxillse, frequently the longest, having six 

 joints, and those of the labium four. The mandibles are smaller, 

 and frequently less dentated in the males than in the opposite sex. 

 The abdomen, united to the thorax by a thread or pedicle, is com- 

 posed of seven rings in the males, and of six in the females. The 

 four wings are always veined. 



The larvae are always destitute of feet, and feed on aliments pre- 

 sented to them by the females or neuters, consisting either of the 

 bodies of Insects, the juices of fruits, or a mixture of pollen, stamina 

 and honey. 



This section is divived into four families. 



FAMILY I. 



HETEROGYNA.(I) 



The first family of our second section is composed of two or 

 three kinds of individuals, the most common of which, the neuters 

 and females, are apterous, and but rarely furnished with very distinct 

 ocelli. 



Their antennae are always geniculate, and the ligula is small, 

 rounded and concave, or cochleariform. 



Some form communities in which we find three kinds of indivi- 

 duals, of which the males and females are winged, and the neuters 

 apterous. In the two last the antennas gradually enlarge, and the 

 length of their first joint is at least equal to that of the third of the 

 whole organ; the second is almost as long as the third, and has the 



(1) Those in which the females differ from the males or are heterogynoiw. 



