1, Bd) are very intimately fused together to form what is called the "lower lip" or labium, a firm transverse plate representing the fused basal portions of the maxillae, which may carry a small median "ligula," representing apparently the fused inner maxillary lobes, a pair of paraglossae (outer maxillary lobes), and a pair of palps.
The inner lobe (lacinia) of the first maxilla terminates in an articulated hook, while in the second maxillae (labium) both inner and outer lobes ("ligula" and "para-glossae") are much Gyrinus sulcatus reduced.
In specialized biting insects, such as beetles (Coleo C ptera), the labium tends to become a hard transverse plate bearing the pair of palps, a median structure - known as the ligula - formed of the conjoined laciniae, and a pair of small rounded processes - the reduced galeae - often called the " paraglossae," a term better avoided since it has been applied also to the maxillulae of Aptera, entirety different structures.
- Diagram of a transverse section through the body-wall of a young Ligula, illustrating the microscopic structure of tapeworms. a.
Ligula, unsegmented externally, occurs in birds.
E, First maxilla; a, cardo; b, stipes; c, galea; d, lacinia; e, palp. B, Second maxillae (Labium); a, mentum; b, ligula (between the two galeae); c, c, palps.
A, mandible; b, c, palp and lacinia of first maxilla; d, e, g, h, mentum, palp, fused laciniae (ligula or "tongue") and galea of 2nd maxillae.
Mxp, Maxillary palp. 1, Ligula or "tongue."
Structurally the Neuroptera are distinguished by elongate feelers, a large, free prothorax, a labium with the inner lobes of the second maxillae fused together to form a median ligula, membranous, net-veined wings without hairy covering, those of the two pairs being usually alike, the absence of abdominal cerci, and the presence of six or eight Malpighian tubes.