The mandibles are usually lost, the labrum is reduced to a narrow transverse sclerite, and the labium is a small flap ( though its palps retain quite large).

上颚消失，上唇化为一，唇化为一（唇须发达）。

The mandibles are usually lost, the labrum is reduced to a narrow transverse sclerite, and the labium is a small flap ( though its palps retain quite large).

上颚消失，上唇化为一条窄横片，下唇化为一小片（下唇须发达）。

The mandibles are usually lost, the labrum is reduced to a narrow transverse sclerite, and the labium is a small flap ( though its palps retain quite large).

上颚消失，上化为一条窄横片，化为一小片（须发达）。

The mandibles are usually lost, the labrum is reduced to a narrow transverse sclerite, and the labium is a small flap ( though its palps retain quite large).

上颚消失，上唇化为一条窄横片，下唇化为一小片（下唇须发达）。

The mandibles are usually lost, the labrum is reduced to a narrow transverse sclerite, and the labium is a small flap ( though its palps retain quite large).

上颚消失，上唇化为一条窄横片，下唇化为一小片（下唇须发达）。

The mandibles are usually lost, the labrum is reduced to a narrow transverse sclerite, and the labium is a small flap ( though its palps retain quite large).

上颚消失，上为一条窄横片，下为一小片（下须）。

The mandibles are usually lost, the labrum is reduced to a narrow transverse sclerite, and the labium is a small flap ( though its palps retain quite large).

上颚消失，上唇化为一条窄横片，下唇化为一小片（下唇须发达）。

The mandibles are usually lost, the labrum is reduced to a narrow transverse sclerite, and the labium is a small flap ( though its palps retain quite large).

上颚消失，上唇化为一条窄横片，下唇化为一小片（下唇须发）。

The mandibles are usually lost, the labrum is reduced to a narrow transverse sclerite, and the labium is a small flap ( though its palps retain quite large).

上颚消失，上唇化为一条窄横片，下唇化为一小片（下唇须发达）。